THE RIGHT WORD
The same person might wince when receiving a flu shot, flinch from a difficult task, and cower in fear at the approach of a tornado. All of these verbs mean to draw back in alarm, disgust, faintheartedness, or servility, but there are subtle differences among them.
To wince is to make a slight recoiling movement, often an involuntary contraction of the facial features, in response to pain or discomfort (: to wince when a singer misses a high note), while flinch may imply a similar drawing-back motion or, more abstractly, a reluctance or avoidance (: to tackle the job without flinching).
Cower and cringe both refer to stooped postures, although cower is usually associated with fearful trembling (: he cowered in the doorway) while cringe is usually linked to servile, cowardly, or fawning behavior (: she cringed before her father's authority).
More than any of the other verbs here, recoil suggests a physical movement away from something (: recoil at the sight of a poisonous snake), although that movement may also be psychological (: recoil at the very thought of a family reunion).
