Ziva had led a really complicated life. She has never really known a time without war and violence and death. She learned very young that people could be endlessly cruel to each other and having lost so many people to war and violence she has no patience for people who want to kill or destroy others. Unfortunately this has also really taught her to close herself off. She's had to protect herself from emotions because she was consistently hurt. The fact is that emotions are dangerous in her business. You have to be hard and tough to survive. And if she fell apart everytime a friend of hers was killed she would spend her entire life in a puddle unable to cope. So she's become a bit hardened to it.
She was very much a tomboy when she was growing up, but over the years working at NCIS her femininity has come to the surface. When she first arrived her staple outfit was cargo pants and a t-shirt and boots. Now she is shown in a much more feminine light. She wears blouses, make up, and tends to straighten her hair. Perhaps this is because she has had a chance to get more in touch with her feminine side, but her style has also developed along with her attraction to Tony. One thing she always wears in a gold Star of David around her throat. This is a connection she keeps to her faith.
Faith is clearly important to her. She is liberal in her religion, she eats food that is not kosher and is not seen following the Sabbath. However, faith is more than a practicing of religion and her faith is very strong. Coming from Israel, it may also be a way that she keeps connected to her history and her religions history. She is also very respectful of the practices of other people. She does not believe there is only way to God, and she hates that people would use faith and religion to bring violence against one another as she grew up seeing in the Middle East. She sees people as people, simple as that. She holds them accountable for their actions.
Before she joins NCIS her tolerance for people who are upset is not very high. She has a hard time dealing with the emotions of others. This is shown in one scene where Gibbs asks her to take information from a woman whose husband was just killed and she is very uncomfortable when the woman clings to her. However, over the years her patience has grown and she is far more gentle with herself and others. This does not mean that she lays her emotions on the table for others to see, but it is easier for people she really trusts to see below the surface.
Also due to the strict and violent life she grew up in, she is not always very good at having fun. She tells Tony that she had to grow up fast or die, and he tells her that she can have fun now because that's over. She is getting better about acting a little childish and letting herself just relax. Tony keeps her from being too serious, and that really helps her relax. Over time she has seen more movies, and does things outside of reading books, which was for the longest time her most used form of entertainment.
Ziva knows quite a few interesting ways to kill people thanks to her training. Some of the unique ways she knows of are paper clips and credit cards. Not that she needs anything at all because she's so well trained she can drop kick someone into next Tuesday. A fact she loves to tease people with. Though she won't hurt anyone needlessly she loves letting people know that she could. She enjoys having them sort of quiver in fear. It gives her a sense of safety to, knowing that can so easily protect herself. She carries three weapons with her at all time: her sig on her let hip, a knife concealed at her waist and a smaller gun at her ankle. She also apparently collects knives and has a very impressive collection.
She is a very loyal individual, though her loyalty has been tested and shifted and threatened by people she had really loved. From being a very young girl she adored her father and her brother. Both eventually betrayed and she suffered greatly because of it. She fell for a man who ended up using her. It takes her a long time to trust, but the team at NCIS has won her over and it is clear that she would die for any of them. In some ways her difficulty trusting has come from the betrayal she has felt over and over. She wants to get close to people, but she is afraid that they may end up hurting her. The other reason she has trouble trusting is because she had lost so many people. Family, friends, and boyfriends, and most of the time she has lost them in violent ways. Her feelings towards herself and trust of herself have also been tested time and time again, forcing her to reevaluate herself and who she is. After nearly being grazed by a bullet, she doubts her abilities. All those doubts and fears however get shoved below the surface.
Ziva is also an extremely sensual woman. Despite that she has never been overly girly, she is often drips sexuality. She is extremely comfortable in her sexuality and in no way feels threatened by men. She can hold her own against men, and in fact that sometimes makes them feel uncomfortable. She is a confident and strong woman. On several occasions she has used her sexuality to get men to cough up information, even having posed as girlfriends or gone as far as to sleep with someone for information. She manages to even intimidate Tony because right from the beginning she flirts with him on his level. It is her idea to pretend to have sex with him to keep the facade of being a married couple up. She lost her virginity in a weapons carrier, and sex is something she really enjoys. While not in any way easy to get into bed, she is seen flirting with men on many occasions and appreciating their bodies. Apparently she screams during sex.
Ziva is highly intelligent. She has a photographic memory, and is fluent in Hebrew, Arabic, English, Spanish, Turkish and French. She also knows Russian, Italian, and German. Knowing so many languages has led to one very amusing quirk. She is not very good at colloquialisms or idioms and is forever messing things up. Tony has taken it upon himself to correct her and she responds with an eye roll or an excuse or will simply make a note of her mistake for use later. She is forever messing things up. She also does not use contractions as often as most native English speaking people do. She is far more like to say "should not" instead of "shouldn't". Though she has been known to use them from time to time.
In the same way that she is not very good dealing with the emotions of others she is not good with her own emotions. She keeps them shut off. If she needs to break down it is often in the bathroom alone or where no one else can see her. She feels that being emotional is weak and she wants to be strong, for herself, for her team, for the people she cares about. She often conflicts with Abby in that sense, because Abby is so open about her emotions that Ziva can't quite understand or relate. In some ways Abby has helped her to show a little bit more tension. It is another way in which she has grown, while once she stiffened at Abby's hugs, she now melts into them, needing and enjoying the closeness of someone she considers her best friend. She will never be a touchy feely person, but there are people she really needs to be close to, and if you are let in and she doesn't stiffen at your hug, it just shows how much she trusts you. Otherwise its best to not take it personally.
She hates to be out of control. Control is how she has managed everything in her life, order in chaos. Once when fighting a marine on steroids she was shoved up against the wall and overpowered, which left her feeling overwhelmed and confused. And intrigued. She really is turned on by powerful men. Though testing that isn't a good thing because she is likely to pin you down to prove to herself that she can. She also uses driving as a way to get control. She drives extremely fast and if given a chance she prefers to be the one driving. Of course, one has to feel for anyone she is driving with. Jenny has suggested that she may have been an Eastern European cab driver in a past life. Her red mini cooper really pushes the limits. When she is feeling out of control or worried and needs to calm her nerves she will clean her gun, even if it is already spotless.
Ziva has a hard time sleeping. She is so alert that the slightest sound will take her out of a sound (or as close as she can get) sleep. Twice now when woken up abruptly she has pulled her gun on the men who woke her up. She sleeps with her gun under her pillow or close by her bed. It is likely her time imprisoned in Africa with Saleem has made sleeping that much more difficult for her.
In her spare time she really loves cooking, and playing the piano. She is seen to be good with children, though she is unsure of whether she will ever get to have her own. Children are some of the only people with whom she is really gentle. It may be partly because she had a much younger sister and feels a need to protect those who are younger than her the way she could not protect her sister. So when it comes to children and teenagers she will go out of her way to be protective.
The best parts of her are often seen in the way other people look at her. She is dearly loved by everyone on the team and they see her as a vital and important member of their family. Ducky often sees her vulnerability in a way only a psychologist can. Abby has taught her how to be a girlfriend and just hang out with another girl and have fun. It is likely that Abby is her first real girlfriend. With McGee she provides the source of a protective older sister and can not help but sometimes partake in Tony's older brotherly teasing. With Gibbs she is the daughter he was unable to protect so long ago, and he is the father figure that she can finally really trust. And Tony, well...its complicated, but there is a real love there, even if they have been unable and unwilling to admit it. Together this family provides her with the stability and normalcy she needs to grow, especially after the horrors in Africa.
But perhaps the best way to describe her is to say that she is a survivor. She really has been through hell and not let it destroy her.