look up any word, like fellated:
 
7.
to mess up a word by mispronouncing it.
I un-derfed my cat.
by Underfed June 05, 2010
 
1.
The face a dog makes when he or she tilts his or her head and looks inquisitive or confused.
I threw the ball and Rover just looked at me like, "derf"?
by smrtpnts December 04, 2011
 
2.
a slang term for dry humping. Involves sexual contact through clothes
Did you get way derfing her last night.
by derfsurfer April 30, 2009
 
3.
A new number that will be made globalized and reprinted into every dictionary, schoolbook, printed onto every calculator, and everywhere else that contains numbers, as of June 27th 2063. It is between 5 and 6 and is a combination fo both. It has the top of a 5 and the bottom of a six.
One, two, three, four, five, derf, six ...
by mizzlefftie012 July 15, 2011
 
4.
Noun:
Someone who is an idiot, annoying person, jerk, etc.

Verb:
The act of doing something stupid, lame or annoying.

Adjective:
Something that is rather lame, tedious, annoying, uncool, bad, etc.
Schmitty: That Shane guy is such a derf.
Joe: Yeah, he really derfed up that photo.
Cameron: It was such a derfy thing to do.
Brodie: Derfalicious indeed.
by camblyth June 20, 2011
 
5.
fred, spelled backwards
yo derf, did you do your homework?
by sakawakag May 06, 2010
 
6.
1. To get a stamp on your completed homework.
2. To act crazy and/or insane while teaching or just talking in general.
3. To yell at one's smart board.
4. To flick off one's class.

5. To stand on a desk to feel if the air is working.
6. To teach "shit"
7. To throw markers at ghetto kids.
Person A: "Yes I derfed my homework!"
Person B: "Ugh, lucky, I skipped one problem."

Teacher: "You guys forgot your calculators?!!!!" "YOU'RE ALL LOSERS!!!!!!"

Teacher: (to smart board) "WHY ISN'T THIS THING WORKING?!"

Students: (to teacher): "Happy Birthday!"
Teacher: *flicks off class and walks out*
by calculusstudent November 23, 2012