ピクッと

adverb

with a twitch; with a jerk; with a flutter

Describes a small, sudden, involuntary movement, often of a body part like an eyebrow, finger, or corner of the mouth. Mimetic adverb.

• 彼かれのまぶたがピクッと動うごいた。

  His eyelid twitched.

• 口くち元もとがピクッと引ひきつった。