1. The expression of not wanting to deal with something at the moment, or finding certain things unappeasable.
Origin: Derived from the phrase "Too Far" which had become too long to say due to laziness, leading the use of just the two letters "T" "F", which also, after so long had become two syllables too many, thus eventually leading to "Tiff."
It is often used to replace phrases such as; "Screw that," "Fuck this," "forget about it," etc.
Nick: Hey man, let's go to the library and get our study on.
Carl: Dude, tiff that.
Girlfriend: You never spend enough time with me!
Boyfriend: Tiff this relationship.