A significantly close sibling, usually a year or two apart. Most commonly misspelled as "Smiffey", and can be shortened to "Smiffz". A "Smiffy" tends to use spaces in between punctuated smiley faces and before/after punctuation.
Smiffy, you are the best big sister in the entire world, let's take a profile picture for our Facebook profiles to show everyone how close we are!
An animator on such popular flash websites as SheezyArt, DeviantArt, and New Grounds. Along with fellow animator, Joanime, he created a unique character called, Smiffy Bagel. Smiffy is usually angry at someone/something.
Guy: Hey, did you see that movie, The Twin Noodles?