def

Short definition from Wiktionary

Noun

1. 1
   Abbreviation of definition.
2. 2
   Abbreviation of deficit.
3. 3
   Abbreviation of diesel exhaust fluid.
4. 4
   Initialism of defence point.
5. 5
   Initialism of daily electronic feed.
6. 6
   Initialism of delayed electronic feed.

Adverb

1. 1
   Clipping of definitely.

Adjective

1. 1
   Excellent; very good.