I perhaps alarm nun more if drunk (5,7)
I believe the answer is:
roman numeral
'i' is the definition.
(I is the Roman numeral for one)
'alarm nun more if drunk' is the wordplay.
'alarm nun more' can be anagrammed to 'ROMAN NUMERAL'.
Though, I am not sure how the anagram is indicated.
'perhaps' acts as a link.
Can you help me to learn more?
(Other definitions for roman numeral that I've seen before include "I for one!" , "I say" , "Eg, X or V or M" , "Such as V, X or L" , "I, perhaps" .)