Fifth wheel

The term “fifth wheel” is internet slang used to describe someone who feels left out or excluded in a social situation. It implies that the person doesn’t have a role or purpose, similar to a fifth wheel on a four-wheel vehicle.

Examples:

1. Emily felt like the fifth wheel when she joined her friends on a double date. They were all paired up and she was the only single person, making her feel left out and awkward.

2. During their online gaming session, Mark joined the group late and found out they were already in the middle of a mission. He felt like a fifth wheel, as all the other players were already engaged in gameplay, leaving him with nothing to do.