billy club vs truncheon

billy club and truncheon both are nouns.

Word	Noun	Adjective	Verb	Adverb
billy club	Yes	No	No	No
truncheon	Yes	No	No	No

As nouns, billy club and truncheon are synonyms defined as:

billy club and truncheon: a short stout club used primarily by policemen

Other synonyms of billy club include baton, billy, billystick, nightstick.

billy club (noun)	truncheon (noun)
a short stout club used primarily by policemen	a short stout club used primarily by policemen