apropos vs apt

apropos and apt both are adjectives.

Word	Noun	Adjective	Verb	Adverb
apropos	No	Yes	No	Yes
apt	No	Yes	No	No

apropos (adjective)	apt (adjective)
of an appropriate or pertinent nature	being of striking appropriateness and pertinence
	(usually followed by `to') naturally disposed toward
	mentally quick and resourceful
	at risk of or subject to experiencing something usually unpleasant

apropos (adverb)	apt (adverb)
at an opportune time
introducing a different topic