hitchhike vs thumb

hitchhike is not a noun while thumb is a noun.

Word	Noun	Adjective	Verb	Adverb
hitchhike	No	No	Yes	No
thumb	Yes	No	Yes	No

As verbs, hitchhike and thumb are synonyms defined as:

Other synonyms of hitchhike include hitch.

hitchhike (noun)	thumb (noun)
	the part of a glove that provides a covering for the thumb
	a convex molding having a cross section in the form of a quarter of a circle or of an ellipse
	the thick short innermost digit of the forelimb

hitchhike (verb)	thumb (verb)
travel by getting free rides from motorists	feel or handle with the fingers
	travel by getting free rides from motorists
	look through a book or other written material