Definition of fall off the back of a lorry in English:

fall off the back of a lorry

phrase

informal
  • (of goods) be acquired in dubious circumstances.

    ‘he sells cheap computer games that have fallen off the back of a lorry’
    • ‘When I was a kid my neighbour was always selling things that seemed to have "fallen off the back of a lorry".’
    • ‘Keep an eye out for pickpockets and remember that many of the things for sale 'fell off the back of a lorry'.’
    • ‘"But it's not like stuffing a few pairs of jeans in your bag or a TV falling off the back of a lorry. This bread is keeping us alive."’