ブーメラン

Borrowed from English boomerang, from Dharug bumariny.^[1]

• (Tokyo) ブーメラン [búꜜùmèràǹ] (Atamadaka – [1])^[1]
• IPA^(key): [bɯ̟ːme̞ɾã̠ɴ]

ブーメラン • (būmeran) 

1. (weaponry) a boomerang (flat curved airfoil)
2. (slang) a harmful action that comes back to the doer
3. (Internet slang) "Is this you?"; "Did you do this?"

• Used by Internet users to point out another user's hypocrisy with their past online posts and comments. 特大ブーメラン (“extra large boomerang”) refers to an action that is more noteworthy or notorious.

• 天(てん)に向(む)かって唾(つば)を吐(は)く (tennimukattetsubaohaku), 天(てん)に唾(つば)す (tennitsubasu), 天(てん)唾(だ) (tenda) (sense 3; literally mean "if you spit at the sky, the spit comes back at you")