v.tr. 1 make clear or intelligible with detailed information etc. (also absol. : let me explain). 2 (foll. by that + clause) say by way of explanation. 3 account for (one's conduct etc.). explain away minimize the significance of (a difficulty or mistake) by explanation. explain oneself 1 make one's meaning clear. 2 give an account of one's motives or conduct. explainable adj. explainer n.
[ L explanare (as EX-(1), planus flat, assim. to PLAIN(1)) ]