underestimate

UK: verb: /ˌʌndərˈɛstɪmeɪt/, noun: /ˌʌndərˈɛstɪmət/

US: /v. ˌʌndərˈɛstəˌmeɪt; n. -mɪt, -ˌmeɪt/

US: (v. un′dər es′tə māt′; n. un′dər es′tə mit, -māt′)

Inflections of 'underestimate' (v): (⇒ conjugate)

underestimates

v 3rd person singular

underestimating

v pres p

underestimated

v past

underestimated

v past p

WordReference Random House Learner's Dictionary of American English © 2025

un•der•es•ti•mate /v. ˌʌndərˈɛstəˌmeɪt; n. -mɪt, -ˌmeɪt/   v., -mat•ed, -mat•ing, n. 
v. [~ + object]

1. to estimate at too low a value, rate, or the like:
   to underestimate the costs; to underestimate an employee.

n. [countable]

2. an estimate that is too low.

un•der•es•ti•ma•tion /ˌʌndərˌɛstəˈmeɪʃən/  n. 

[countable] an underestimation of the impact on costs.

[uncountable] guilty of some minor underestimation.

WordReference Random House Unabridged Dictionary of American English © 2025

un•der•es•ti•mate  (v. un′dər es′tə māt′;n. un′dər es′tə mit, -māt′), v., -mat•ed, -mat•ing, n. 
v.t. 

1. to estimate at too low a value, rate, or the like.

v.i. 

2. to make an estimate lower than that which would be correct.

n. 

3. an estimate that is too low.

• under- + estimate 1805–15

un′der•es′ti•ma′tion, n. 
Synonyms

• 1. undervalue, underrate, misjudge, miscalculate.

Collins Concise English Dictionary © HarperCollins Publishers::

underestimate / ˌʌndərˈɛstɪˌmeɪt/ verb (transitive)

1. to make too low an estimate of: he underestimated the cost
2. to think insufficiently highly of: to underestimate a person

noun / ˌʌndərˈɛstɪmɪt/

1. too low an estimate

ˌunderˌestiˈmation noun

USAGE
Underestimate is sometimes wrongly used where overestimate is meant: the importance of his work cannot be overestimated (not cannot be underestimated)