[grin] vi grinned ; grin.ning [ME grennen, fr. OE grennian; akin to OHG grennen to snarl] (bef. 12c): to draw back the lips so as to show the teeth esp. in amusement or laughter; broadly: smile -- grin n -- grin.ner n -- grin.ning.ly adv
GRIN
Meaning of GRIN in English
Merriam-Webster English vocab. Английский словарь Merriam Webster. 2012