guestimate

[verb ges-tuh-meyt; noun ges-tuh-mit, -meyt]

guesstimate

or gues·ti·mate

[verb ges-tuh-meyt; noun ges-tuh-mit, -meyt]Informal.
verb (used with object), guess·ti·mat·ed, guess·ti·mat·ing.
  1. to estimate without substantial basis in facts or statistics.
noun
  1. an estimate arrived at by guesswork.

Origin of guesstimate

1935–40, Americanism; blend of guess and estimate
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2018

British Dictionary definitions for guestimate

guesstimate

guestimate

noun (ˈɡɛstɪmɪt)
  1. an estimate calculated mainly or only by guesswork
verb (ˈɡɛstɪˌmeɪt)
  1. to form a guesstimate of
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

Word Origin and History for guestimate

guesstimate

v.

1902, a blending of guess (v.) and estimate. Related: Guesstimated; guesstimating. As a noun, from 1906.

Online Etymology Dictionary, © 2010 Douglas Harper