Isn't relevant to western alliance (4)
I believe the answer is:
nato
'alliance' is the definition.
(NATO is an example)
'isn't relevant to western' is the wordplay.
I cannot quite understand how this works, but
'to' is found in the answer.
The remaining letters 'na' is a valid word which might be clued in a way I don't understand.
This explanation may well be incorrect...
Can you help me to learn more?
(Other definitions for nato that I've seen before include "Military alliance, formed 1949" , "Security agreement" , "Military/political alliance" , "Military alliance (acronym)" , "Transatlantic alliance" .)