One succeeding taking a cape off (7)
I believe the answer is:
inexact
'off' is the definition.
(both can mean imprecise)
'one succeeding taking a cape' is the wordplay.
'one' becomes 'i' (Roman numeral).
'succeeding' becomes 'next' (synonyms).
'taking' is an insertion indicator.
'cape' becomes 'c' (abbreviation used on maps).
'a'+'c'='ac'
'next' placed around 'ac' is 'nexact'.
'i'+'nexact'='INEXACT'
(Other definitions for inexact that I've seen before include "estimated?" , "not precisely correct" , "Not precise, approximate" , "Fuzzy - untrue" , "Rough" .)