Soldier in Irish uniform (9)
I believe the answer is:
irregular
'soldier' is the definition.
The answer and definition can be both people as well as being singular nouns.
Perhaps there's an association between them I don't understand?
'irish uniform' is the wordplay.
'irish' becomes 'IR' (abbreviation).
'uniform' becomes 'regular' (similar in meaning).
'ir'+'regular'='IRREGULAR'
'in' is the link.
Can you help me to learn more?
(Other definitions for irregular that I've seen before include "unlike full-time soldiers" , "Not uniform" , "Abnormal" , "Rough - dishonest" , "Rough - guerrilla" .)