look up any word, like dirty sanchez:
Mostly used and originated in Southern Africa. Used to signyfy something that is disguisting, putrid or grosse.
1) Crap is siff.
2) The vagrant smells siff
by Ru March 09, 2005
A word originating in South Africa. Mostly used by young people to describe something that is repulsing, disgusting, gross, revolting, etc.
"Dude, I was walking in the park and I stepped in some runny dog poo, it was so siff!"
"How can you date that girl?! She is so siff!"
"Don't pick you nose dude, it's freaking siff!"
by CapeTownKitty July 09, 2013
background as far as i know is from Australia, possily S.A.

meaning of siff is: "as if"
"siff like slipknot"
"siff be a gay Brenny"(look up brenny)
by poopooman March 20, 2005
Secret Internet Fatty Fat
Beccaboo is a SIFF.

That girl is a SIFF.
by AllieMae June 19, 2007