cosh vs bludgeon

cosh and bludgeon both are nouns.

Word	Noun	Adjective	Verb	Adverb
cosh	Yes	No	Yes	No
bludgeon	Yes	No	Yes	No

As nouns, bludgeon is a hypernym of cosh; that is, bludgeon is a word with a broader meaning than cosh:

cosh: a piece of metal covered by leather with a flexible handle; used for hitting people
bludgeon: a club used as a weapon

cosh (noun)	bludgeon (noun)
a piece of metal covered by leather with a flexible handle; used for hitting people	a club used as a weapon

cosh (verb)	bludgeon (verb)
hit with a cosh, usually on the head	strike with a club or a bludgeon
	overcome or coerce as if by using a heavy club