Immensely adv. : In immense manner or degree.

Example:
Who else thinks Michael Keaton is an Immensely underrated Actor?

Taxonomy
Merriam-Webster Online Dictionary, mense, Dictionary, webster, Word Games, Webster Online Dictionary with audio pronunciations, Middle English, thesaurus, measure, glossary, language, ESL, Search, adjective, Etymology, Middle French, Latin, past participle.

Defination from the web:
immense from the Merriam-Webster Online Dictionary with audio pronunciations, thesaurus, Word of the Day, and word games. ... 1 : marked by greatness especially in size or degree; especially : transcending ordinary means of measurement <the immense and boundless universe> ...