Commercial dressings primarily frustrate nurses (6)
I believe the answer is:
advert
'commercial' is the definition.
(I've seen this before)
'dressings primarily frustrate nurses' is the wordplay.
'primarily' indicates taking the first letters.
'frustrate' becomes 'avert' (I am not sure about this - if you are sure you should give a lot more credence to this answer).
'nurses' is an insertion indicator (nurse can mean to hold onto or harbour).
The first letter of 'dressings' is 'd'.
'd' placed into 'avert' is 'ADVERT'.
Can you help me to learn more?
(Other definitions for advert that I've seen before include "Commercial notice" , "Refer or allude" , "Plug (abbr)" , "Promotional display" , "Draw attention to" .)