grin

laugh, smile, giggle, grin, beam, sneer

名词 grin:

1. a facial expression characterized by turning up the corners of the mouth; usually shows pleasure or amusement
   同义词：smile, smiling, grinning

动词 grin:

1. to draw back the lips and reveal the teeth, in a smile, grimace, or snarl

1. They grinned with pleasure when I gave them the sweets.
   当我给他们糖果时，他们高兴地咧开嘴笑了。
2. I knew she was joking because she had a big grin on her face.
   我知道她是在开玩笑，因为她脸上堆满笑容。

grin

v.（动词）
grinned,grin.ning,grins
v.intr.（不及物动词）
To draw back the lips and bare the teeth, as in mirth or good humor.
咧嘴而笑：嘴唇后咧并露出牙齿，如在高兴或情绪好时
v.tr.（及物动词）
To express with a grin:
咧嘴而笑地表示：
例句：
I grinned my approval.
我咧嘴一笑表示赞许

n.（名词）
The act of grinning.
咧嘴一笑：咧嘴一笑的动作
The facial expression produced by grinning.See Synonyms at smile
笑：咧嘴而笑地显示出的面部表情参见 smile

来源：
Middle English grennen [to grimace]
中古英语 grennen [怪相，鬼脸]
from Old English grennian
源自 古英语 grennian

【引伸】
grin.ner
n.（名词）
grin.ningly
adv.（副词）