watcher vs private security force

watcher and private security force both are nouns.

Word	Noun	Adjective	Verb	Adverb
watcher	Yes	No	No	No
private security force	Yes	No	No	No

watcher (noun)	private security force (noun)
a guard who keeps watch	a privately employed group hired to protect the security of a business or industry
a close observer; someone who looks at something (such as an exhibition of some kind)
a person who keeps a devotional vigil by a sick bed or by a dead body