enlighten

Etymology

Formerly also inlighten, from Middle English enlightenen, inlightnen, a hybrid formed from inlighten (“to enlighten, illuminate”), from Old English inlīhtan, onlīhtan, enlīhten (“to enlighten, illuminate, give light to, give sight to”) and lightnen (“to enlighten, illuminate”) (equivalent to light + -en). Cognate with Dutch inlichten (“to enlighten, inform”), Old High German inliuhten (“to enlighten, illuminate”), Gothic 𐌹𐌽𐌻𐌹𐌿𐌷𐍄𐌾𐌰𐌽 (inliuhtjan, “to enlighten, illuminate”). More at inlight, -en.

verb

1. (transitive) To supply with light.
   The sun enlightens the Earth.
2. (transitive, figurative) To make something clear to (someone); to give knowledge or understanding to.
   There was a warning sulkiness in the manner of this speech, which admonished Mr Pecksniff that his dear friend was not to be trifled with or fenced off, and that he must either return a straight–forward reply to his question, or plainly give him to understand that he declined to enlighten him upon the subject to which it referred. 1844, Charles Dickens, chapter 20, in Martin Chuzzlewit
   As your reviewer showed, the purpose of the translator and publishers is to help along the labor movement by furnishing a lesson from the past to enlighten the movement of to-day. August 27 1904, John Hossack, “The Mysteries of the People”, in New York Times
   Rather than focus on true-to-life drama that might have enlightened viewers, the BBC, frightened by Tory politicians’ threats to its very existence, concentrated its dramatic output on inaccurate historical soap operas, that falsified the view of our past. 30 October 2016, Bernie Evans, “The big issue: where the true blame lies for our dangerous politics of hate”, in The Guardian