Here are a few slang words that you can use, just be careful with some of them as some are negative.
This means gossip.
You have to tell me the dirt on Penny. Something is just not right with her.
This is someone who is boring or someone who brings everyone down.
Fred is being such a drag. Let’s not invite him to go out with us next time.
This is someone who is weak and/or timid.
Don’t be such a wuss. Just come horseback riding with us!
This word means the same thing as a wuss. Someone who is weak and/or timid.
You are such a wimp. Just be a man and do your thing.