Wiktionary
cool one's heels
vb. (context idiomatic English) To wait, especially impatiently or restlessly.
WordNet
cool one's heels
v. wait or pass the time aimlessly or futilely; be kept waiting; "She kicked her heels for hours at the gate of the Embassy" [syn: kick one's heels]
Usage examples of "cool one's heels".
The waiting room was more like a book-lined private study than a place to cool one's heels.