def
Excellent, cool, or very good; in casual writing it can also shorten definitely.
By Cal Hewitt, Founder at Web Leveling · Researched from public sources ·
What it actually means
Def is an approving adjective associated with hip-hop-era slang, as in "That track is def." In messages, def can also be a practical shortening of definitely, as in "I am def coming." The two uses have different grammar: the praise use describes something, while the other intensifies agreement or certainty.
See the quick definition in the def dictionary entry.
Where it came from
Dictionary.com records def as slang for "excellent; first-rate" and dates that sense to 1980-85. It became strongly associated with hip-hop culture through 1980s usage, but no single person is reliably documented as its coiner.
No single person is credited, the origin is commonly reported.
Where it's popular
U.S. hip-hop culture and the broader English-language pop culture influenced by it.
Def Jam's 1984 founding is one visible marker of the word's close cultural association with hip-hop, but the label did not coin the slang.
How it caught on
- 1980-85Dictionary.com dates the slang adjective def, meaning excellent or first-rate, to this period.
- 1984Def Jam Recordings is founded, making def a highly visible word in hip-hop branding.
- 1985LL COOL J releases Radio on Def Jam, part of the label's early rise.
- 1990sDef remains recognizable in rap, youth culture, and mainstream media as a compliment.
How to use it
“That beat is def.”
Praising music or another creative work.
“Your jacket is def.”
Giving someone an enthusiastic compliment.
“I am def going to the show.”
Using def as a text shorthand for definitely.
Common mix-ups
Def is not automatically short for definitely. When it means excellent, it is an adjective; when it means definitely, it is a written shorthand with a different role.
Do you actually know it?
How def is your def knowledge?
0/31. What does "That song is def" mean?
2. When did Dictionary.com date the slang sense of def?
3. Which sentence uses def as a shortcut for definitely?
Related slang
Questions people ask
What does def mean in slang?
As slang, def means excellent, cool, or first-rate.
Is def short for definitely?
It can be in casual texts, but the older slang sense means excellent.
Who coined def?
No single coiner is reliably documented. Dictionaries date the slang sense to the early 1980s.
Def Jam was founded in 1984, but its name is evidence of the word's hip-hop visibility, not proof that the record label invented it.