- to wait or take rest
- it has also been extensively used for those who are awaiting some sort of chastisement
- to be detained or obliged to wait
- The prisoner has been awarded the death penalty is cooling his heels until the President evaluates if mercy can be sanctioned.
- Their journey is still far from over. They will cool their heels tonight at a five star hotel to commence travelling again from morning.
- The man works so hard for his family, he deserves to cool his heels every now and then.
- You will burn yourself out if you do not cool your heels when you can.
- You cannot keep cooling your heels and then expect work to be done.
- The group of bikers riding through the country since last nine days were left to cool their heels overnight at a very inexpensive inn last night.
The energy used in walking causes the feet to become hot and hence the phrase gets its current meaning, which is to wait.
The origination of the phrase comes from the 1500's where cooling the heels of horses was a common phenomenon in long travels. The earliest literary use came from the year 1576 but back then it was 'cooling the feet' rather than heels.
The speculation is that the feet have been replaced by the word heels over the centuries that the phrase has been used.