twitch

A brief, small (sometimes involuntary) movement out of place and then back again; a spasm.

I saw a little twitch in the man's face, and knew he was lying.

Action of spotting or seeking out a bird, especially a rare one.

A stick with a hole in one end through which passes a loop, which can be drawn tightly over the upper lip or an ear of a horse and twisted to keep the animal quiet during minor surgery.

THE TWITCH is a short stick of strong ash, about the size of a mopstick, with a hole pierced near the end, through which is passed a piece of strong but small cord, and tied in a loop large enough to admit the open hand freely.

A brief, contractile response of a skeletal muscle elicited by a single maximal volley of impulses in the neurons supplying it.

The sudden narrowing almost to nothing of a vein of ore.

To perform a twitch; spasm.

His fingers were nervously twitching.

To cause to twitch; spasm.

Their feet padded softly on the ground, and they crept quite close to him, twitching their noses...

To jerk sharply and briefly.

to twitch somebody's sleeve for attention

Thrice they twitched the diamond in her ear.

To exert oneself.

To spot or seek out a bird, especially a rare one.

Marsh Sandpiper [...] This delicate ‘mini shank’ has graced our shores for the past six successive years and has become increasingly easy to twitch.

"But the key revelation from twitching that wonderful Iceland Gull on 10 March 1974 wasn't its eroticism. It was the sheer innocence of it."

couch grass (Elymus repens; a species of grass, often considered as a weed)