noun
smirk; affected smile; fake laugh
A smile or laugh that is not genuine; often carries a negative nuance of insincerity or mockery.
彼は私の失敗を見て、似非笑いを浮かべた。
He gave a smirk when he saw my mistake.
その政治家は質問に対して似非笑いでごまかした。
The politician dodged the question with an affected smile.
Compound of 似非 (ese, 'pseudo, fake') and 笑い (warai, 'laugh, smile'). The exact historical derivation is uncertain, but the word has been used since at least the Edo period to describe insincere smiles.