Definition of backseat driver in US English:

backseat driver

noun

informal
  • 1A passenger in a car who gives the driver unwanted advice.

    • ‘I would need a sound proof partition for my passengers, though - I can't stand back seat drivers.’
    • ‘I can't stand back-seat drivers… even worse, passenger-seat drivers.’
    1. 1.1 A person who is eager to advise without responsibility.
      • ‘He was also plagued by advisers, officials and politicians, in Delhi who were not just back-seat drivers but wanted to take over the steering wheel themselves.’
      • ‘‘I'll be in the driving seat because it's the only seat to be in,’ he answered a conference delegate who pointedly asked what the candidates thought of back-seat drivers.’
      • ‘She failed to appreciate that the term ‘back-seat driver’, in most people's eyes, was pejorative: she thought it merely indicated helpfulness, whereas others saw it as meddling and controlling.’
      • ‘He is deluged with advice from back-seat drivers.’
      • ‘After all, remember how he once described critics as back-seat drivers facing the wrong way, and certainly critics are usually pretty good on the past, moderately good on the present, and helpless and hopeless for the future.’

Pronunciation

backseat driver

/ˌbaksēt ˈdrīvər/