Welshwoman has knowledge about whiskey (4)
I believe the answer is:
gwen
'welshwoman' is the definition.
Both the definition and answer are singular nouns.
Maybe you can see a link between them that I can't see?
'knowledge about whiskey' is the wordplay.
'knowledge' becomes 'gen' (I've seen this before).
'about' is an insertion indicator.
'whiskey' becomes 'W' (phonetic alphabet: alpha, bravo, charlie etc.).
'gen' going around 'w' is 'GWEN'.
'has' acts as a link.
Can you help me to learn more?
(Other definitions for gwen that I've seen before include "Sister of Augustus John" , "name" .)