A smash-and-grab is a fast, crude robbery: the thief breaks the shop window (or the glass display case inside), grabs what is nearest — usually jewellery, phones, expensive small things — and runs, all in under a minute. The whole point is speed. There is no clever plan, no picking of locks; the thief accepts that an alarm will go off and simply bets on being gone before anyone arrives. You will see it used two ways. Most often it sits in front of a noun: a smash-and-grab raid, a smash-and-grab robbery, smash-and-grab thieves. It can also stand alone as a noun — 'there was a smash-and-grab at the jeweller's last night.' It is normal newspaper and police English, not slang, though it is a little informal in feel. People also stretch it away from crime, to mean anything done quickly and greedily with no care for what is left behind. A company that buys a firm, sells off its buildings and walks away may be said to have done a smash-and-grab. In sport, a team that defends for ninety minutes and scores once at the end has taken a smash-and-grab win. Note the hyphens: they hold the three words together into one describing-word.