ape

Concise Oxford English Dictionary © 2008 Oxford University Press:
ape/eɪp/

▶noun

• 1 a large tailless primate of a group including the gorilla, chimpanzees, orang-utan, and gibbons. [Families Pongidae and Hylobatidae.]

• 2 informal an unintelligent or clumsy person.

• 3 archaic an inferior imitator.

▶verb (apes, aping, aped) imitate, especially in an absurd or unthinking way.

– phrases
go ape (or N. Amer. vulgar slang apeshit) informal become very angry or excited.

– origin OE apa, of Gmc origin.