[adj] easily excited [adj] (physiology) capable of responding to stimuli
high-keyed, irritable, nervous, quick, sensitive, skittish, spooky, warm
unexcitable
agitable, all nerves, apprehensive, bearish, bitchy, cankered, cantankerous, churlish, combustible, crabbed, cranky, cross, cross-grained, crusty, cussed, disagreeable, edgy, emotional, emotionally unstable, eruptive, explosive, fearful, feisty, feverish,