Stretched nurses down for shifts this evening (7)
I believe the answer is:
tonight
'this evening' is the definition.
(synonyms)
'stretched nurses down for shifts' is the wordplay.
'stretched' becomes 'tight' (I've seen this before).
'nurses' is an insertion indicator (nurse can mean to hold onto or harbour).
'down for shifts' becomes 'on' (I can't justify this - if you can you should believe this answer much more).
'tight' going around 'on' is 'TONIGHT'.
Can you help me to learn more?
(Other definitions for tonight that I've seen before include ""Not ____, Josephine!"" , "West Side Story number" , "The end of today" , "Got thin (anag)" , "Selection from West Side Story" .)