trembling

Trembling is a reflex motion caused by cold, fear, or excitement. It can also denote instability.

Often depicted in art with short, wavy motion lines surrounding the outline of the body. (see Danbooru post #1630828)
Sharper, less subtle lines depict twitching, which is more violent and momentary.

Not to be confused with ^^^, which expresses reaction.

See also

• shaking
• twitching

External Definition

The Free Dictionary