Account by America — time I have a word in case that’s objective (10)
I believe the answer is:
accusative
'a word in case that's objective' is the definition.
(as in the accusative case in grammar)
'account by america time i have' is the wordplay.
'account' becomes 'acc'.
'by' is a charade indicator (letters next to each other).
'america' becomes 'usa' (United States of America).
'time' becomes 't' (abbreviation).
'i have' becomes 'I've' (contraction of 'I have').
'acc'+'usa'+'t'+'ive'='ACCUSATIVE'
(Other definitions for accusative that I've seen before include "Grammatical case" , "prosecuting" , "Tending to charge" , "Case which needs objective" , "Case expressing the object of an action" .)