tremulous

Marked by trembling, quivering, or shaking.

Marked by a rapid varying between pitches or tones.

Timid or fearful.

Trembling; shaking; quivering; vibrating; unsteady.

Lacking firmness, resolution, or courage; feeble; wavering; timid.

In entomology, finely wavy: as, a tremulous line.

Shaking; shivering; quivering.

Affected with fear or timidity; trembling.

Trembling, quivering, or shaking.