Clear former partner with single charge (9)
I believe the answer is:
exonerate
'clear' is the definition.
(synonyms)
'former partner with single charge' is the wordplay.
'former partner' becomes 'ex' (an ex-partner).
'with' is a charade indicator (letters next to each other).
'single' becomes 'one' (synonyms).
'charge' becomes 'rate' (rate is a kind of charge).
'ex'+'one'+'rate'='EXONERATE'
(Other definitions for exonerate that I've seen before include "Justify" , "Officially absolve from blame" , "Declare to be blameless (9)" , "Pronounce not guilty of a crime" , "Free of duty" .)