cowardice, wince, flinch, hesitate, waver
怯 centers on a fearful, hesitant reaction: cowardice, flinching, wincing, or wavering in the face of something intimidating.
怯 combines 忄 (heart/mind) with 去 (go away), suggesting a heart that wants to retreat from fear. The exact historical development is uncertain, but the phono-semantic structure is plausible.
The heart 忄 wants to go away 去: when you're scared, your heart flinches and you hesitate.
For キョウ, imagine a cowardly character named Kyo who always flinches and wavers: Kyo -> キョウ, and his heart 忄 wants to run away 去.
cowardly; craven
being startled, surprised or afraid; panic; trepidation
to become frightened; to be frightened (of); to be scared (of)
to falter; to flinch (from); to recoil (from); to quail (at); to be intimidated; to feel daunted; to be discouraged; to hesitate
to play a dirty trick; to use underhanded methods; to hit below the belt; to play foul
very mean (sneaky); extremely unsportsmanlike
coward; chicken; yellow-belly
coward; timid man
coward
cowardly; spineless; weak-willed; fainthearted