noun
ominous smile; dark smile; creepy smile
Internet slang for a sinister or unsettling smile, often used in fictional or meme contexts to describe a character's expression.
彼の暗黒微笑に、周りの人はみんな震え上がった。
Everyone around trembled at his ominous smile.
そのキャラのダークネススマイリングが怖すぎる。
That character's dark smile is way too creepy.
Standard Japanese for an eerie or uncanny smile; 暗黒微笑 is a stylized, internet-born term with a more dramatic, fictional connotation.
Coined from the kanji 暗黒 (darkness) and 微笑 (smile), assigned the gikun reading ダークネススマイリング, a phonetic rendering of English 'darkness smiling'. Likely originated in online communities as a dramatic or humorous way to describe a sinister smile.