guesstimate

or gues·ti·mate

[verb ges-tuh-meyt; noun ges-tuh-mit, -meyt]Informal.
See more synonyms for guesstimate on Thesaurus.com
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 guesstimate

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 guesstimate
v.

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

Online Etymology Dictionary, © 2010 Douglas Harper