grin like a Cheshire cat

Verb

(simile) To smile broadly, especially in a self-satisfied way.

Japanese Meaning

得意げに、にんまりと笑う / 自己満足気に大きく笑う / 周囲に自己の満足感を誇示する笑い方をする

When she saw her exam score, she couldn't help but grin like a Cheshire cat.

試験の結果を見たとき、彼女は思わず満足そうににやりと笑った。

Sense（1）

(simile) To smile broadly, especially in a self-satisfied way.

grins like a Cheshire cat

（ present singular third-person ）

grinning like a Cheshire cat

（ participle present ）

grinned like a Cheshire cat

（ participle past ）

grinned like a Cheshire cat

（ past ）