Thorough review of a card I left (7)
I believe the answer is:
radical
'thorough' is the definition.
(as in a radical or thorough overhaul of something)
'review of a card i left' is the wordplay.
'review of' indicates anagramming the letters.
'left' becomes 'l' (common abbreviation).
'a'+'card'+'i'='acardi'
'acardi' is an anagram of 'radica'.
'radica'+'l'='RADICAL'
(Other definitions for radical that I've seen before include "Sweeping - reformer" , "One who favours thoroughgoing reform" , "Militant" , "left-winger" , "Politically extreme" .)