(of the voice) quivering as from weakness or fear; "the old lady's quavering voice"; "spoke timidly in a tremulous voice"
If someone's voice, smile, or actions are tremulous, they are unsteady because the person is uncertain, afraid, or upset. She fidgeted in her chair as she took a deep, tremulous breath. + tremulously tremu·lous·ly `He was so good to me,' she said tremulously. shaking slightly, especially because you are nervous (tremulus; TREMBLE)