It rouses after the manner of strong spirit (6)
I believe the answer is:
alarum
'it rouses' is the definition.
The definition suggests a singular noun which matches the answer.
'after the manner of strong spirit' is the wordplay.
I cannot quite see how this works, but
'after' could be 'ala' ('a la' - 'in the style of ' or 'after' in French) and 'ala' is found within the answer.
'spirit' could be 'rum' (alcoholic spirit) and 'rum' is present in the answer.
No letters remain.
This may be the basis of the clue (or it may be nonsense).
Can you help me to learn more?
(Other definitions for alarum that I've seen before include "commotion" , "Warning bell (archaic)" , "conflict" , "Warning sound" , "disturbance" .)