Die hard = Fanatical
Osaka is filled with die hard Tigers fans.
A feather in your cap = A reward of some kind
After a great deal of difficulty, the salesman got his order. That was a feather in his cap.
To bounce back = To recover
After hard training, it's difficult for me to bounce back.
To be down = Not to operate
Since my P.C. is old, it's down more than it's up.
To be up for = To want something
After training I'm always up for a cold drink.
To be on the ball = To be ready or to be aware
If you want to succeed in this world, you must be on the ball at all times.
To be whipped = To be very tired
After a tough day, I am really whipped.
To rock on = To continue even though it's difficult
If life is getting you down, take a break and then rock on.
To dim = To turn down light, power etc.
To save electricity, we must dim our lights and air conditioning.
To have your heart set on something = To want to do something very, very badly
I have my heart on going to Chicago to watch my daughter dance.