edge - advantage, brink⏎
flyer - leaflet⏎
leverage - influence, upper hand⏎
fickle - changeable, unreliable⏎
hallmark - sign, feature, indication, standard (of quality of something)⏎
malfunction - fail, stall, break down⏎
exhibition - show, display, presentation⏎
manage - control, run, undertake, supervise, conduct⏎
key - most essential, most important, main, chief thing, crucial influential⏎
languish - fail, become weaker, be affected⏎