Guesstimate is a colloquial neologism formed by combining guess and estimate. It is synonymous with both those words. As a noun, it’s usually pronounced GUESS-tuh-mitt. As a verb, it’s usually GUESS-tuh-mate.
Guesstimate might be considered out of place in formal writing. It’s often used to affect the kind of cutesy tone that is more likely to annoy readers than amuse them. But it is increasingly used in earnest, especially in American writing (the word is probably American in origin). Based on our nonexhaustive research, it seems to appear most often in Midwestern publications.
We haven’t seen him on the big screen since the 2007 “Rush Hour 3,” and can’t even guesstimate the last time he did stand-up. [Chicago Tribune]
I call them the forlorn 30 percent of Chicago, a guesstimate, mostly black communities on the South and West sides where no investment occurs. [Chicago Sun-Times]
But officials acknowledge that is a bit of a guesstimate until developers undertake a new round of soil tests. [Minneapolis Star Tribune]
You’ll have to guesstimate the other costs, based on how often you typically use healthcare and what you use. [Los Angeles Times]