Excuse individual after jumping bail (5)
I believe the answer is:
alibi
'excuse' is the definition.
(excuse given by a suspect in an investigation)
'individual after jumping bail' is the wordplay.
'individual' becomes 'i' (Roman numeral for one).
'after' means one lot of letters go next to another.
'jumping' indicates anagramming the letters.
'bail' is an anagram of 'alib'.
'i' put after 'alib' is 'ALIBI'.
(Other definitions for alibi that I've seen before include "Defence used by an accused person" , "Courtroom evidence" , "Evidence one was not present" , "Making excuse" , "Fact of being elsewhere (legal)" .)