Defined:  Apropos is defined as doing something when it is a good time to do it. (adverb) A check arriving in the mail the day before your rent is due is an example of the check arriving apropos. The definition of apropos is something that is connected to a certain situation. (adjective) If a lawyer refers to a previous court ruling in a similar case, that referral would be apropos to the current case.  (YourDictionary definition and usage example. Copyright © 2013 by LoveToKnow Corp.)

We are in hurricane season.  How apropos that makes my post defining proffered.  My posting having exhibited good timing makes apropos in the preceding sentence an adjective.

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More Definitions:

1 : at an opportune time : seasonably 2 : by way of interjection or further comment : with regard to the present topic

Examples of APROPOS <I went up to New York last weekend; apropos, have you seen your New York cousins lately?>

Origin of APROPOS:  French à propos, literally, to the purpose

First Known Use: 1668