One who goes out for lunch with anyone, anywhere.
I thought I saw Mike at lunch yesterday with Jenifer at Wendy's?
Yeah, and here he is today with Tara at Taco Bell.
I'd never go out with that lunch slut!
One who will happily go out to lunch with the first person or group of people that come to get them regardless of previous conversations or verbal commitments to go out to lunch with others.
These people often suffer from lonelylunchaphobia which is the fear of having to go out to eat lunch alone.
Jared: Where is Peter, he said he wanted to go to lunch?
Dan: Let me text him and find out where he is.
Ricardo: That lunch slut is probably already gone.
Text from Peter: Already at El Camps eating lunch with Brett
Jared, Dan, and Ricardo: What a lunch slut!