What it means
Means a man or guy, with a slightly old-fashioned, polite vibe. It can sound a bit posh or countryside, like someone in a Barbour, but it’s used everywhere from offices to pubs. Call someone a good chap and you’re saying he’s decent, helpful, and reliable. You’ll also hear chaps as a friendly hello to a group. Sometimes it’s said with a wink, mildly patronising.
Usage examples
"New chap at work sorted my laptop in two minutes, wouldn’t take a tenner, just said no worries. Proper good chap, bought him a pint after."
"A jolly chap called Henry came round to fix the boiler, finished the job in twenty minutes flat."
"You're a good chap for picking up the dry-cleaning on your way home, you've saved my Saturday."
"Sound chap, that one. Held the lift for me, then pointed me to the right office when I was wandering about like a lost uncle."
"Morning, chaps. Who’s nicked my charger and why’s it sitting under Gary’s desk like it pays rent?"
Where it comes from
It comes from Middle English chapman, meaning a trader or hawker. Over time that got shortened and loosened up into chap, which stopped meaning a merchant and started meaning just a man or fellow. That older lineage is why the word still has a faint polite, old-school, slightly tweedy feel to it.