To cough or clear one's throat so as to draw attention.
an exclamation or cough to get attention
the sound of a quiet cough or of clearing one's throat
an exclamation of disapproval or annoyance
an exclamation to indicate sarcasm
Forcibly, sometimes mutedly, expelling air from one's lungs, sometimes to clear mucus, sometimes to attract attention to something; less vigorous than coughing.