Definition of a nasty piece (or bit) of work in English:

a nasty piece (or bit) of work

phrase

British
informal
  • An unpleasant or untrustworthy person.

    ‘if you ask me he's a nasty piece of work’
    • ‘Until last week he was out on parole, having served more than half of a seven-year sentence for being a nasty piece of work.’
    • ‘Don't rely on Lady Fortune: I know her well, and she can be a nasty piece of work at times!’
    • ‘Altogether a nasty piece of work, but a delight to get into the head of and write.’
    • ‘Convention says that the Florentine civil servant, power-broker and writer, Niccolo Machiavelli, was a nasty piece of work.’
    • ‘He is a nasty piece of work, and has to go, but there must be other ways to sort this out.’
    • ‘He was a nasty piece of work and generally was avoided by the other prisoners who knew his reputation.’
    • ‘He's widely known to be a nasty piece of work and I hope he gets long suspension.’
    • ‘Your behaviour makes it clear that you are a nasty piece of work who abuses those who love you in order to get what you want.’
    • ‘A womaniser, unfaithful, just a nasty piece of work.’
    • ‘She is a nasty piece of work and people used to give her a very wide berth.’