Scorer's very "detailed” attack (5)
I believe the answer is:
assai
'scorer's very' is the definition.
I can't tell whether this definition defines the answer.
'detailed attack' is the wordplay.
'detailed' means to remove the last letter (the word must be end-less or 'de-tailed').
'attack' becomes 'assail' (synonyms).
'assail' with its last letter removed is 'ASSAI'.
Can you help me to learn more?
(Other definitions for assai that I've seen before include "Very (in music scores)" , "For a conductor, very" , "Palm tree" , "Very (in musical score)" , "small, purple, nutritional fruit" .)