Something surprising or shocking that makes you suddenly understand or realize something you didn't know before.
Compound of 'eye' and 'opener' (from 'open,' via Old English 'openen'). The metaphor suggests something that opens your eyes to new understanding, emerging in 19th-century American English.
An eyeopener is literally something that jolts your consciousness—the phrase captures how surprise physically changes your facial expression, showing how language mirrors the body's reaction.
Complete word intelligence in one call. Free tier — 50 lookups/day.