This word is acceptable for play in the US & UK dictionaries that are being used in the following games:

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adj. Marked by trembling, quivering, or shaking.

adj. Timid or fearful; timorous.

adj. Trembling, quivering, or shaking.

adj. Timid, hesitant, or unconfident.

adj. Shaking; shivering; quivering.

adj. Affected with fear or timidity; trembling.

Trembling; shaking; quivering; vibrating; unsteady.

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

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

adj. (of the voice) quivering as from weakness or fear

"Pool clapped his hands, and the little maid ran out of the house to him in tremulous, fluttery haste."

unsteady   

trembling    vibratory    tremulous poplar   

tremble    tremor   

shaking    shivering    quivering    trembling    quaking    wavering    timid   

plaintive    breathless    feverish    wistful    unsteady    mournful    husky    faint    nervous    dreamy