v. grinned, grin·ning, grins
To smile broadly, often baring the teeth, as in amusement, glee, embarrassment, or other strong emotion.
To express with a grin: I grinned my approval.
1. The act of grinning.
2. The facial expression produced by grinning.
[Middle English grennen, to grimace, from Old English grennian.]
The American Heritage® Dictionary of the English Language, Fifth Edition copyright ©2019 by Houghton Mifflin Harcourt Publishing Company. All rights reserved.
Indo-European & Semitic Roots Appendices
Thousands of entries in the dictionary include etymologies that trace their origins back to reconstructed proto-languages. You can obtain more information about these forms in our online appendices:
The Indo-European appendix covers nearly half of the Indo-European roots that have left their mark on English words. A more complete treatment of Indo-European roots and the English words derived from them is available in our Dictionary of Indo-European Roots.