Claire is pretty much super lazy and she loves to sleep and relax a lot. This is due to her being the smartest of all the Demon-Hunters, as well as having telekinesis and telepathy as her special abilities, which kinda lead to her becoming super lazy since she doesn't need to get up to do stuff.
The only times when she's not lazy is either when she's hunting demons, or when she's having a competition with Ferania, as she's having a lot of fun doing those things.
Claire likes to dress cool, act cool, and making silly entrances (which she honestly thinks are cool) when appearing on the scene. In her free time she reads a lot of books, she particularly enjoys stories about legendary heroes.
Since Claire can read minds, it's pretty difficult to take her by surprise, but if she's actually surprised she easily panics and forgets to use her abilities.