湧く【わく】
to well (up), to gush out (of water), to spring out, to surge, to appear (esp. suddenly) (sweat, tears, etc.), to sweat, to cry, to feel emotions (e.g. joy, bravery, etc.), to spring up (e.g. an idea, emotions, clouds), to well up, to arise, to hatch, to breed, to propagate, to be infested (esp. of parasitic insects, etc.)