Underestimate v. t. : To set to/ low a value on; to estimate below the truth.

Underestimate n. : The act of underestimating; too low an estimate.

Example:
Why do some parents sometimes think about themselves only and some adults Underestimate kids?

Taxonomy
Merriam-Webster Online Dictionary, Dictionary, webster, mate, Word Games, Webster Online Dictionary with audio pronunciations, thesaurus, Google Search, Custom Search, glossary, english, language, ESL, Search, n-d, transitive verb, estimate, actual size.

Defination from the web:
underestimate from the Merriam-Webster Online Dictionary with audio pronunciations, thesaurus, Word of the Day, and word games. ... Learn more about "underestimate" and related topics at Britannica.com. Pronunciation Symbols. Share this entry: Link to this page: Cite ...