accelerando accelerate acceleration accost advance aggravate aggravation amplify approach appropinquate approximate bear down on bear down upon bear up beef up beefing-up blow up blowing up blowup charge close close in close with come come closer come forward come near come on come up complicate concentrate concentration condensation condense confront consolidate consolidation crack on deepen deepening double draw near draw nigh drive electrify encounter energize enhance enhancement exacerbate exacerbation exaggerate exaggeration explosion gain ground gain upon galvanize generate getaway hasten heat up heating-up heighten heightening hop up hot up hurry hurry up impetus information explosion intensification intensify jazz up key up loop in magnification magnify make complex narrow the gap near open the throttle pick up speed pickup plug in population explosion proximate put on put on steam quicken quickening race ramify redouble redoubling reinforce reinforcement rev shake up sharpen shock short short-circuit sidle up to soup up speed up speedup step down step on it stiffen strengthen strengthening switch off switch on thrust tightening triple turn off turn on whet