Side- friend 

A person in which you have developed a friendship with but you are also having sexual relations with this person as well.

That’s be my side- friend through out my whole relationship

Side- friend by Side friend December 10, 2017

Side Friend 

Someone you talk to that you really don't care about.

my side friend was annoying to talk to

Side Friend by tbonehuber November 3, 2010

Side Friend 

Someone you only call when your real friends are busy.

I was really bored, so I hung out with my side friend.

Side Friend by mike937 May 4, 2016

Side Friend 

Someone you don’t treat the same as your other friends. Like you could be all hyper and having fun with your friend then once they’re unavailable you talk to your side friend and don’t act the same and act more dry with them. Also the side friend can show more and participate more in the “friendship” while the “friend” is only talking to them just to talk to them waiting for their real friend to call them back

*On FaceTime with a friend* (Hyper, talking a lot, laughing a lot)
*On FaceTime with a side friend* (Dry, barely talking, could repeating the same simple word after the side friend says something)

Side Friend by I.IS.THAT.BITCH July 7, 2019

Side Friend 

A side friend is a person you are 'friends' with because your other friend is friends with them. So basically your just friends with them because your friend Becky is too. So when you, Becky and that person are all talking, you guys are all considered friends, but if you were left alone with that side friend, it would be awkward to keep a convo going because you guys aren't really friends without Becky there.

You consider your side friend as one of your friends, but deep down inside you know you guys don't really talk without someone thats both of your friends.

"Me and Emma are side friends, if we were left alone it would be so weird"

Side Friend by Crackers and Cheese April 24, 2017

Side Friend 

A friend of someone that has other, closer friends that they would rather be with.

"*Sigh* I'm such a side friend..."
"What's a side friend?"
"Someone who you're friends with, but still have closer friends"
"Oh, like Jeremy!"

Side Friend by SpookyScarySakura October 8, 2020

Rebound Side-Friend Dick (RSFD)

When a girl goes after the male friend of a guy who just rejected her

Jim and Jane broke up
Jim's best friend Kyle is now Jane's Rebound Side-Friend Dick (RSFD)

Jane wants Kyle's dick
Kyle and Jane hook up

Rebound Side-Friend Dick (RSFD) by KingSwagger February 14, 2012