Source : Webster's Revised Unabridged Dictionary (1913)

Undue \Un*due"\, a.
   1. Not due; not yet owing; as, an undue debt, note, or bond.

   2. Not right; not lawful or legal; improper; as, an undue
      proceeding. --Bacon.

   3. Not agreeable to a rule or standard, or to duty;
      disproportioned; excessive; immoderate; inordinate; as, an
      undue attachment to forms; an undue rigor in the execution
      of law.

   {Undue influence} (Law), any improper or wrongful constraint,
      machination, or urgency of persuasion, by which one's will
      is overcome and he is induced to do or forbear an act
      which he would not do, or would do, if left to act freely.
      --Abbott.

Source : WordNet®

undue
     adj 1: not yet payable; "an undue loan" [syn: {not due}] [ant: {due}]
     2: not appropriate or proper (or even legal) in the
        circumstances; "undue influence"; "I didn't want to show
        undue excitement"; "accused of using undue force" [ant: {due}]
     3: lacking justification or authorization; "unreasonable
        searches and seizures"; "desire for undue private profit";
        "unwarranted limitations of personal freedom" [syn: {unjustified},
         {unwarranted}]
     4: beyond normal limits; "excessive charges"; "a book of
        inordinate length"; "his dress stops just short of undue
        elegance"; "unreasonable demands" [syn: {excessive}, {inordinate},
         {unreasonable}]