To attack verbally, to criticise excessively.(verb)
To take immediate action regarding; to avail oneself of without delay.(verb)
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Use "jump on" in a sentence
"It got its start—and a jump on other potential competitors—when in 1887 Emile Levassor, the “L” of P&L, met Gottlieb Daimler, the founder of the company that today builds the Mercedes-Benz."
"We bike ride, disco dance, jump on the trampoline, Roller-Blade, ice-skate, or bodysurf at the beach."
"Ever since Nicky Hilton came out with Chick, rich girls everywhere are trying to jump on the designer bandwagon."