Cane son roughly when drinking whiskey (5)
I believe the answer is:
swish
'cane' is the definition.
Although both the answer and definition are singular nouns, I don't see how they can define each other.
'son roughly when drinking whiskey' is the wordplay.
'son' becomes 's' (genealogical abbreviation for son).
'roughly' becomes 'ish' (I am not sure about this - if you are sure you should give a lot more credence to this answer).
'when drinking' is an insertion indicator.
'whiskey' becomes 'W' (phonetic alphabet: alpha, bravo, charlie etc.).
's'+'ish'='sish'
'sish' placed around 'w' is 'SWISH'.
Can you help me to learn more?
(Other definitions for swish that I've seen before include "Smart; stylish" , "Extravagant" , "Smart, fashionable" , "Stylish (sl.)" , "Classy" .)