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[adv] at an opportune time; "your letter arrived apropos" [adv] by the way; "apropos, can you lend me some money for the weekend?" [adj] of an appropriate or pertinent nature
apposite, appropriate, apt, incidentally, pertinent, seasonably, timely, well-timed
malapropos
a propos, about, ad rem, adapted, admissible, against, anent, appertaining, applicable, applying, apposite, appropriate, apropos of, apt, as for, as regards, as respects, as to, becoming, befitting, belonging, by the by, by the way, concerning, dovetailin