def
adverb
definitely.
def
1 American
[def]
/ dɛf /
adverb
Informal.
def
2
American
[def]
/ dɛf /
adjective
def.
3
American
abbreviation
-
defective.
-
defendant.
-
defense.
-
deferred.
-
defined.
-
definite.
-
definition.
def.
1
British
abbreviation
def
2
British
/ dɛf /
adjective
Etymology
Origin of def1
By shortening
Origin of def2
An Americanism dating back to 1980–85; of uncertain origin
Example Sentences
Examples are provided to illustrate real-world usage of words in context. Any opinions expressed do not reflect the views of Dictionary.com.
"If you're looking for a mental break from the world def get Pokopia, it's like therapy," US-based influencer Ashley Duncan wrote on X.
From Barron's • Mar. 11, 2026
In text overlaid on the clip, she promised: “This week I go off on the podcast.. def going to ruffle some feathers & I didn’t stutter.”
From Los Angeles Times • Apr. 23, 2024
There’s an intimacy to a book that we can’t get from a movie or a TV show, no matter how true it is — even in 3-D, in the highest of high def.
From New York Times • Apr. 27, 2023
“And we def have to catch up for drinks before you leave.”
From Washington Post • Apr. 7, 2023
“Oh, yes! I want to def —” He ignored her outburst.
From "Gathering Blue" by Lois Lowry
Definitions and idiom definitions from Dictionary.com Unabridged, based on the Random House Unabridged Dictionary, © Random House, Inc. 2023
Idioms from The American Heritage® Idioms Dictionary copyright © 2002, 2001, 1995 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company.
