Wally’s clothing for golf hotel after dark (5)
I believe the answer is:
night
'after dark' is the definition.
'wally's clothing for golf hotel' is the wordplay.
'wally' becomes 'nit' (I've seen this before).
'clothing for' means one lot of letters goes inside another.
'golf' becomes 'g' (phonetic alphabet: alpha, bravo, charlie etc.).
'hotel' becomes 'h' (phonetic alphabet: alpha, bravo, charlie etc.).
'g'+'h'='gh'
'nit' placed around 'gh' is 'NIGHT'.
(Other definitions for night that I've seen before include "'The 2 8 of the dog in the _____'" , "- School, - owl" , "For most, the time for sleep" , "Dark hours" , "Time of darkness" .)