What it means
Means run away fast, either because you're late or because something's kicked off and you don't fancy sticking around. It's that panicky, arms-flapping sprint, not a heroic jog. You can leg it from the police, from an awkward convo, or just to catch the last bus. Common everyday British phrasing.
Usage examples
"Oi, the 38's already pulling off and I've left my Oyster on the table, grab your coat and leg it before it goes."
"When the bouncer clocked us, we legged it down the alley and didn't stop till the bus stop."
Where it comes from
Dead literal really, you use your legs to leg it. The phrase has been knocking about British slang for ages, the idea being that when trouble shows up your legs do the thinking and the rest of you just follows at speed.
Other ways to say it
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