quavering

/K W EY1 V ER0 IH0 NG/
verb
  1. 1

    To shake in a trembling manner.

  2. 2

    To use the voice in a trembling manner, as in speaking or singing.

  3. 3

    To utter quaveringly.

noun
  1. 1

    The act of something that quavers.

adjective
  1. 1

    Trembling, or prone to trembling and shaking.

Source: https://en.wiktionary.org/wiki/quaver, https://en.wiktionary.org/wiki/quavering