For others like me who are unfamiliar with the word tenacity: "The state or quality of being tenacious", which in turn is "Holding or tending to hold persistently to something, such as a point of view" or "Tending to retain; retentive".
While we're at it, you should also read this: http://www.google.com/search?q=complement+vs+compliment
I double-click the word, and get "If you have tenacity, you are very determined and do not give up easily."