A silf is a "sister i'd like to fuck". it is the same idea as a milf. Silfs are usually absolutely georgous, sexy, irresistable, and extremely flirty
by alwaysaladybug February 03, 2011
An unusual spelling of the girl's name Alexis, that happens to be way cooler than the traditional spelling, much like the girl with that name. A girl with this name is typically pretty, funny, smart, talented, hardworking, organized, flirty, fun, and slightly clumsy. She is a good friend and loves to laugh.
Guy to his friend: "Have you met that hot new girl....She's a total Alxis!! I'm working up the nerve to talk to her!"
by alwaysaladybug January 19, 2011