Feather in one’s cap
An achievement for which one is recognized
- It's a real feather in our cap to be playing in the state championship.
Allowed to avoid mandatory tasks
- Susan was excused boots for the party cleanup because she has an exam tomorrow.
All talk and no trousers
Prone to empty boasts
- He says he's going to complain to the manager, but he's all talk and no trousers.
First in, best dressed
The first people to do something will have an advantage
- Come on, the first hundred customers today get a free gift! First in, best dressed!
Knock someone’s socks off
- I'm going to take you to a restaurant that'll knock your socks off.
- He may be old hat among the trendy younger generation, but his shows draw more viewers than any other comedian.
Throw down the gauntlet
To issue a challenge
- A price war looks likely now that a leading supermarket has thrown down the gauntlet to its competitors.
Quake in one’s boots
To be very frightened
- The very thought of a hurricane blowing in makes me quake in my boots.
Keep it under your hat
Don’t tell anyone; don’t reveal this secret
- Look, if I tell you something, will you promise to keep it under your hat?