As a noun imbecile
is (obsolete) a person with limited (
l) (
l) who can perform (
l) and think only like a young child, in medical circles meaning a person who lacks the capacity to develop beyond the mental age of a normal five to seven-year-old child.
As an adjective imbecile
is (dated) destitute of strength, whether of body or mind; feeble; impotent; especially, mentally weak.
As a verb bad is
to simulate.