thug vs crook

thug and crook both are nouns.

Word	Noun	Adjective	Verb	Adverb
thug	Yes	No	Yes	No
crook	Yes	No	Yes	No

As nouns, crook is a hypernym of thug; that is, crook is a word with a broader meaning than thug:

thug: an aggressive and violent young criminal
crook: someone who has committed a crime or has been legally convicted of a crime

Other hypernyms of thug include criminal, felon, malefactor, outlaw.

thug (noun)	crook (noun)
an aggressive and violent young criminal	a long staff with one end being hook shaped
	someone who has committed a crime or has been legally convicted of a crime
	a circular segment of a curve

thug (verb)	crook (verb)
Acting like a criminal or antisocially but with positive connotations	bend or cause to bend