Men's or boys' underpants with a branching seam at the front in the shape of an upside-down Y.
- ‘He's over in the kitchen area, wearing nothing but his hat and a baggy pair of Y-fronts.’
- ‘Good news: Y-fronts are back - only now they are called hip-briefs.’
- ‘So what if he is pictured on his hotel balcony in his Y-fronts?’
- ‘Every man and his brother buys their Y-fronts at this shop.’
- ‘They'll be donning capes and Y-fronts over their trousers.’