- grin (v.)
- Old English grennian "show the teeth" (in pain or anger), common Germanic (cognates: Old Norse grenja "to howl," grina "to grin;" Dutch grienen "to whine;" German greinen "to cry"), from PIE root *ghrei- "be open." Sense of "bare the teeth in a broad smile" is late 15c., perhaps via the notion of "forced or unnatural smile." Related: Grinned; grinning.
- grin (n.)
- 1630s, from grin (v.).
