How to say "jerk" in Japanese

• ピクピク動くピクピクうごく
  expression, godan verbCovers the physical sense of jerking or wiggling, describing repeated small movements. A less common choice; it suits bodies or objects twitching or jolting with quick, repeated motion.
• 躍度やくど
  nounThis is the physics sense only: jerk as the rate of change of acceleration over time. It is not used for a jerkish person or a sudden bodily movement, and is uncommon outside technical contexts.
• ピクつく
  godan verb, intransitive verbFor involuntary twitches or quick jerks, such as an ear twitching. A less common but natural verb for small sudden movements of the body or its parts.

For physical twitching use 「ピクつく」 or 「ピクピク動く」 (「ピクつく」 for ears and similar quick twitches); 躍度 is the physics term for jerk as the derivative of acceleration.

Usage comparisons are AI-assisted and cross-checked by multiple models; for study reference only

• ピクピク動くピクピクうごくto jerk
• 躍度やくどjerk
• ピクつくto twitch (e.g. of ears)
• しゃくるto jerk (one's chin)