Mix of imbecile and sire. One who is at once a person of wealth and status and at the same time a total imbecile. Can also be used in regard to a person of supreme idiocy, a king of imbeciles so to speak.
Mom has a new boyfriend, but I think she is just with him because of his wealth and status. After speaking with him for five minuites, it was clear to me that he is a total imbesire.