riddle vs communicate

riddle is a noun but communicate is not a noun.

Word	Noun	Adjective	Verb	Adverb
riddle	Yes	No	Yes	No
communicate	No	No	Yes	No

As verbs, communicate is a hypernym of riddle; that is, communicate is a word with a broader meaning than riddle:

Other hypernyms of riddle include intercommunicate.

riddle (noun)	communicate (noun)
a coarse sieve (as for gravel)
a difficult problem

riddle (verb)	communicate (verb)
explain a riddle	transmit thoughts or feelings
set a difficult problem or riddle	transmit information
speak in riddles	be in verbal contact; interchange information or ideas
pierce with many holes	receive Communion, in the Catholic church
separate with a riddle, as grain from chaff	administer Communion; in church
spread or diffuse through	join or connect
	transfer to another