A Shakespearean character needs it back by Monday (5)
I believe the answer is:
timon
'a shakespearean character' is the definition.
(Timon of Athens)
'it back by monday' is the wordplay.
'back' is a reversal indicator.
'by' means one lot of letters go next to another.
'monday' becomes 'Mon' (short for Monday).
'it' back-to-front is 'ti'.
'ti'+'mon'='TIMON'
'needs' acts as a link.
(Other definitions for timon that I've seen before include "part of Shakespeare" , "legendary misanthrope" , "-- of Athens (play)" , "Greek misanthrope in play" , "Shakespearean Athenian" .)