Definition of fuck you in US English:

fuck you

exclamation

vulgar slang
  • Used to express anger, defiance, or contempt.

    ‘“Fuck you,” she repeats and slaps him across his face’

noun

vulgar slang
  • An expression of anger, defiance, or contempt.

    ‘the album was a resounding fuck you to those who had written her off’

adjective

vulgar slang
  • Expressing anger, defiance, or contempt.

    ‘a fuck you attitude’