Sillybilly
A person, who acts in a special way and is not afraid to do so. Usually a small, cute, person who is very happy and can make you laugh whenever they want to. Also some one who is very fun to be around and acts in the silliest way possible.
Why are you so cute, you sillybilly.
SillyBilly
A homosexual. Another word substitute to get around the big tech word filters on various apps/sites.
I'm getting some real sillybilly vibes from that guy Chris, watch yourself out there.