Apropos means regarding or appropriate to, as in: Apropos of your interest in fishing, your grandfather gave you his set of championship lures, rods, reels and lucky tackle box.
Apropos is a useful word to learn. But first you have to know how to pronounce it: AP-rə-pō. Then you can conveniently change the subject of a conversation by using the expression "Apropos of nothing," which is a glib way of saying, "Oh, and by the way..." If someone's remarks are suitable and appropriate to the occasion, you can get on their good side by saying: How apropos!
adj of an appropriate or pertinent nature
suitable for a particular person or place or condition etc
apposite, apt, pertinent
being of striking appropriateness and pertinence