sleuth vs spy

sleuth and spy both are nouns.

Word	Noun	Adjective	Verb	Adverb
sleuth	Yes	No	Yes	No
spy	Yes	No	Yes	No

As verbs, sleuth and spy are synonyms defined as:

Other synonyms of sleuth include snoop, stag.

sleuth (noun)	spy (noun)
a detective who follows a trail	(military) a secret agent hired by a state to obtain information about its enemies or by a business to obtain industrial secrets from competitors
	a secret watcher; someone who secretly watches other people

sleuth (verb)	spy (verb)
watch, observe, or inquire secretly	secretly collect sensitive or classified information; engage in espionage
	watch, observe, or inquire secretly
	catch sight of
	catch sight of; to perceive with the eyes