bludgeon vs cosh

bludgeon and cosh both are nouns.

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

As nouns, cosh is a hyponym of bludgeon; that is, cosh is a word with a more specific, narrower meaning than bludgeon:

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

Other hyponyms of bludgeon include blackjack, sap.

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

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