Clear individual pursuing old lover, gaining speed (9)
I believe the answer is:
exonerate
'clear' is the definition.
(synonyms)
'individual pursuing old lover gaining speed' is the wordplay.
'individual' becomes 'one' (an individual is one person).
'pursuing' says to put letters next to each other.
'old lover' becomes 'ex' (I've seen this in other clues).
'gaining' says to put letters next to each other.
'speed' becomes 'rate' (rate is a kind of speed).
'one' put after 'ex' is 'exone'.
'exone'+'rate'='EXONERATE'
(Other definitions for exonerate that I've seen before include "Release" , "Clear of blame" , "Declare to be free from blame" , "let off the hook" , "free of charge" .)