Flinch/flɪntʃ/ Definition 1 of 2Pro Tip 1/3Physical Reaction Flinch often refers to an involuntary body response to unexpected events or fear. She flinched when the bee buzzed near her ear. Pro Tip 2/3Sudden Movements The movement is usually a quick twitch or jerk away from the source of surprise or discomfort. He flinched as the nurse prepared the injection. Pro Tip 3/3Not Always Fear Flinching can occur even in non-fearful situations as a reflex to sudden stimuli. The bright flash made him flinch.