k for kys - people who are all talk and no action, and still think they'

people who are all talk and no action, and still think they're cool

My brother is k for kys. He says he'll beat me up but runs away when I tackle him.

That guy in the gym is k for kys. He says he's strong but can't lift a dumbbell.

My friend is k for kys. He says he'll be rich but still has a job.