Stands for the Sick depressed feeling you get when you see a person/couple who are so beautiful and you know they will never be yours/you will never be in such a painfully beautiful relationship that you just have to sit on your bed and cry.
omg the guy in this film is so hot, why is my boyfriend not that beautiful and sentimental? I have sdf :(
by *gsedj* December 17, 2012
SDF stands for smoke drink fuck
ayo B i wanna do a SDF you down?
by lil blam loc February 29, 2008
Super Dimension Fortress, a public access free unix system which started as an Apple ] BBS in 1981. Today they use alpha servers running UNIX. www.freeshell.org
I have an SDF account.
by UnixFrker February 23, 2005