Officer consumed by joy in mountainous valley (7)
I believe the answer is:
glencoe
'mountainous valley' is the definition.
The definition suggests a singular noun which matches the answer.
'officer consumed by joy' is the wordplay.
'officer' becomes 'NCO' (abbreviation for non-commissioned officer).
'consumed by' means one lot of letters goes inside another (inserted letters get consumed).
'joy' becomes 'glee' (I've seen this in another clue).
'nco' placed into 'glee' is 'GLENCOE'.
'in' acts as a link.
Can you help me to learn more?
(Other definitions for glencoe that I've seen before include "Site of massacre in Scotland in 1692" , "Scottish mountain valley" , "Valley near Ben Nevis" , "Scots valley where Campbells massacred McDonalds" , "Death Valley" .)