Source : Webster's Revised Unabridged Dictionary (1913)

Debtor \Debt"or\, n. [OE. dettur, dettour, OF. detor, detur,
   detour, F. d['e]biteur, fr. L. debitor, fr. debere to owe.
   See {Debt}.]
   One who owes a debt; one who is indebted; -- correlative to
   creditor.

         [I 'll] bring your latter hazard back again, And
         thankfully rest debtor for the first.    --Shak.

         In Athens an insolvent debtor became slave to his
         creditor.                                --Mitford.

         Debtors for our lives to you.            --Tennyson.

Source : WordNet®

debtor
     n : a person who owes a creditor; someone who has the obligation
         of paying a debt [ant: {creditor}]