plainclothesman vs tec

plainclothesman and tec both are nouns.

Word	Noun	Adjective	Verb	Adverb
plainclothesman	Yes	No	No	No
tec	Yes	No	No	No

As nouns, tec is a hypernym of plainclothesman; that is, tec is a word with a broader meaning than plainclothesman:

Other hypernyms of plainclothesman include detective, investigator, police detective.

plainclothesman (noun)	tec (noun)
a detective who wears civilian clothes on duty	a police officer who investigates crimes