勝手に, かってに
Adverb
arbitrarily, of its own accord, without asking, voluntarily, willfully, as one pleases, selfishly, by itself, automatically
書類は勝手にいじられた形跡があった。
勝手にしろ, かってにしろ
Expression, Interjection
have it your way, to hell with you!, get rooted!, bugger you!
勝手にしやがれ, かってにしやがれ
work of art, literature, music
Breathless (1960 film), À bout de souffle