adj. frightened; quivering

'Tremulous' comes from Latin 'tremulus' meaning trembling or shaking. It describes someone who is quivering from fear, nervousness, or weakness. The word is often used to describe voices, hands, or entire demeanor. 'Craven' means cowardly but not necessarily quivering, 'succulent' means juicy, and 'congenial' means pleasant or friendly - none match the definition.