Tremulous means trembling slightly with nerves or weakness. A voice that will not hold quite steady.
Voices and hands are its usual subjects, and a tremulous smile is one that might collapse into tears. The word is formal and literary, and it carries sympathy rather than criticism. Light and water can be tremulous too, meaning quivering. The related everyday words are trembling and shaky, and a tremor is the medical noun for an involuntary shake.
1adjectivetremulousShaking slightly from nervousness or weakness.
“She answered in a tremulous voice.”
Tremulous, tremor and tremble are three forms of one Latin verb. Tremō meant to tremble or shake, and its descendants came into English by three separate doors.
Proto-Indo-European
*trem-
Latin
tremulus
English, today
tremulous
Built from
From Latin tremulus, from tremō (“to tremble, shake”) + -ulus. a doublet of tremor and tremble. by surface analysis, tremulate + -ous.
Etymology from Wiktionary, CC BY-SA