Excuse me! I see Australian runner removing uniform (4)
I believe the answer is:
ahem
'excuse me' is the definition.
(both might be said to get someone's attention)
'i see australian runner removing uniform' is the wordplay.
'i see' becomes 'ah' (exclamation used to indicate understanding).
'australian runner' becomes 'emu' (I've seen this in another clue).
'removing' is a deletion indicator.
'uniform' becomes 'U' (phonetic alphabet: alpha, bravo, charlie etc.).
'emu' with 'u' taken away is 'em'.
'ah'+'em'='AHEM'
(Other definitions for ahem that I've seen before include "It's said to gain attention; ah, me (anag.)" , "Exclamation attracting attention" , "Cough to draw attention" , "Gentle utterance to attract attention" , "Utterance of mild disapproval" .)