When you give a quivering and uncertain smile because you are nervous, this is an example of a smile that would be described as tremulous.
Origin of tremulous
- From Latin tremulus from tremere to tremble
From American Heritage Dictionary of the English Language, 5th Edition
- From Latin tremulus, from tremÅ (“I shake"). Cognate to Ancient Greek Ï„ÏÎÎ¼Ï‰ (trÃ©mÅ).