also: ぴくりともうごかない
expression
completely still; not moving a muscle
Emphasizes absolute stillness, often of a person or animal that does not move even slightly. The mimetic ピクリ represents a tiny twitch or flinch.
彼はピクリとも動かないで、じっと私を見つめていた。
He stared at me without moving a muscle.
猫はピクリとも動かずに、鳥を観察していた。
The cat watched the bird, completely still.
The mimetic adverb ピクリ (or ぴくり) represents a slight, sudden movement or twitch. Combined with the negative form of 動く (to move), the phrase literally means 'not moving even a twitch'.