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1.
Shortened version of the word definately.
Man: Wanna go to the mall?

Boy: YEA DEFLY.
by Rafffffiiiiiiiiiio September 16, 2005
 
2.
a slang term for definitely.
Defly, is definitely a strong and usable term in the English grammar to describe something as persistent and accurate.
by Nhi October 21, 2007