"Um ... excuse me" (4)

I believe the answer is:
ahem
'um excuse me' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Other definitions for ahem that I've seen before include "Excuse me!" , "Throat clearance to attract attention" , "Expression of disapproval" , "Sound used to attract attention" , "Cough to draw attention" .)