Quivering p. pr. & vb. n. : of Quiver

Example:
How do you stop your mouth from Quivering during presentations?

Taxonomy
quiver, Merriam-Webster Online Dictionary, Dictionary, webster, Word Games, Webster Online Dictionary with audio pronunciations, thesaurus, Middle English, Old English, Google Search, Custom Search, glossary, english, language, ESL, Search, intransitive verb, Inflected.

Defination from the web:
quiver from the Merriam-Webster Online Dictionary with audio pronunciations, thesaurus, Word of the Day, and word games. ... Etymology: Middle English, probably from quiver agile, quick; akin to Old English cwiferlice zealously. Date: 15th century : to shake or move ...