Green’s Dictionary of Slang

an obnoxious person; a stupid person.

1946		(con. 1912) B. Marshall George Brown’s Schooldays 23: It is the brainless, infinitive-splitting cretin.
1953		T. Williams Camino Real Block Seven: Hold the lady’s chair, cretino!
1957		R. Prather Always Leave ’Em Dying 56: In a couple of years they’ll promote you to cretin.
1962		H. Livings Nil Carborundum (1963) Act I: I try to keep one good cook in each mess [...] That burglarious young cretin that’s just gone was one of the best.
1970		T. Southern Blue Movie (1974) 14: The same rear master-shot [...] of some cretin’s buttocks thrusting half-heartedly into some dopey girl’s black-stockinged honey-pot.
1986		F. Taylor Auf Wiedersehen Pet Two 187: Is this your idea of a joke, you cretin?
1991		C. Hiaasen Native Tongue 310: ‘They’re only tourists.’ [...] ‘Cretins.’.
2004		Guardian G2 5 Oct. 27: It’s called a boom, you cretin.