Is her middle name - Idioms by The Free Dictionary
be (one's) middle name (redirected from is her middle name)
be (one's) middle name
To be a trait that one strongly possesses or readily displays. Lynn is a great listener—compassion is her middle name.
be somebody’s middle ˈname (informal) used to say that somebody has a lot of a particular quality: ‘Patience’ is my middle name!