Is its thin end at the western extremity? (5)
I believe the answer is:
wedge
'is its thin end' is the definition.
I can't tell whether this defines the answer.
'at the western extremity?' is the wordplay.
'at' is a charade indicator (letters next to each other).
'the western' becomes 'w'.
'extremity?' becomes 'edge' (edge is a kind of extremity).
'w'+'edge' is 'WEDGE'.
Can you help me to learn more?
(Other definitions for wedge that I've seen before include "Jam" , "A golf club; divisive idea" , "It may cause division" , "Triangular, thick piece" , "Lofting golf club" .)