Fig. conceited; self-important. (*Typically: act ~; be ~.) Mary is very unpopular because she's so full of herself.She doesn't care about other people's feelings. She's too full of herself.
Conceited, self-centered, as in Ever since she won the prize Mary's been so full of herself that no one wants to talk to her . This expression uses full of in the sense of "engrossed with" or "absorbed with," a usage dating from about 1600.