What it means
A punter is an ordinary customer, punter, or member of the public, especially in UK service talk like pubs, clubs, gigs, shops, and events. Staff use it for the people coming through the door and spending money, sometimes warmly, sometimes with a tiny eye-roll. It also keeps its betting meaning for someone having a gamble, and in some contexts it can mean a sex worker's client.
Usage examples
"Boss asks if the punters are happy. I tell him they're loving it, buying rounds and sticking tenners on the horses like it's nothing."
"We had a few hundred punters through the door on opening night, which for a tiny gallery is a roaring success."
"Get the doors open, the punters are already queuing in the rain and they're not here for the atmosphere alone."
"The band's late, the lager's gone warm, and the punters are starting to look properly mutiny-ish."
"The punters won't care that the soundcheck ran long if the bar's moving and the band's on fire by nine."
Where it comes from
It starts in British betting slang, where a punter was the person putting money down on a wager. That sense is old and well established in UK English. From there it drifted into pubs, venues, shops, and events for the paying public, especially when staff are talking about customers as a group.
