picket vs watchman

picket and watchman both are nouns.

Word	Noun	Adjective	Verb	Adverb
picket	Yes	No	Yes	No
watchman	Yes	No	No	No

As nouns, watchman is a hypernym of picket; that is, watchman is a word with a broader meaning than picket:

Other hypernyms of picket include security guard, watcher.

picket (noun)	watchman (noun)
a form of military punishment used by the British in the late 17th century in which a soldier was forced to stand on one foot on a pointed stake	a guard who keeps watch
a wooden strip forming part of a fence
a vehicle performing sentinel duty
a detachment of troops guarding an army from surprise attack
a protester posted by a labor organization outside a place of work
a person employed to keep watch for some anticipated event

picket (verb)	watchman (verb)
fasten with a picket
serve as pickets or post pickets