To make too low an estimate of the quantity, degree, or worth of.(verb-transitive)
An estimate that is or proves to be too low.(noun)
American Heritage(R) Dictionary of the English Language, Fifth Edition. Copyright (c) 2011 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.
Use "underestimate" in a sentence
"One point you may underestimate is how deeply liberals believe that rich-getting-richer really is hurting the middle class and how the middle class, too, is deserving of lots of social help — if not total egalitarian-type redistribution."
"This is crucial, because it shows that the leaders again underestimate the intelligence of the people, including their moderate supporters."
"That works out to just over $8/gal to generate $800 billion/yr in revenue in the very short term, but a long-term underestimate given that an $8/gal tax would lower demand considerably."