1. Secret Internet Fatty; 2. Any person who takes flattering photos of themselves to hide their bulging fat rolls and dosn't put up a disclamer to those who seem to be ... interested.
"So I met this girl on myspace right. We talked for weeks and figured it was time to hang out and get a cup of coffee. Oh man, I walked in and took one look at her ... yelled SIF and then promptly left. It was horrid"