subject to sudden, involuntary starts, esp. from nervousness, fear, excitement, etc.

characterized by sudden starts, jerks, or jumps

a jumpy narrative.

adjective

calm , collected , composed , easy-going , laid-back

adjective

agitated , antsy * , anxious , apprehensive , creepy * , excitable , excited , fidgety , frisky , high-strung * , jittery , on edge * , on pins and needles , restless , sensitive , shaky , skittish , spooked , tense , timorous , unrestful , nervous , restive , twitchy , antsy , frightened , uneasy , uptight