Green’s Dictionary of Slang

1. an unpleasant person.

1940

S. Sterling ‘Ten Carats of Lead’ in Black Mask Stories (2010) 234/2: The crut who put the bump on that blonde is named Gorilla George.

2. unpleasant, disgusting matter.

1940		E. Hemingway For Whom the Bell Tolls 150: Goat crut.
1947		I. Shulman Amboy Dukes 50: I got the crut.
1955		J.P. Donleavy Ginger Man (1958) 102: No use getting meself upset by the crut.
1964		R. Abrahams Deep Down In The Jungle 265: Crut – Variant of crud, originally, dried semen which sticks to clothes, body, etc., after emission, but more generally referring to anything base.

3. an unspecifed disease.

1947

‘Imaginary Diseases’ in AS XXII:4 Apr. 304/2: crut (the). A variant of Crud, usually modified locally. The most common form is the Senegambian Crut.