\Ought\ ([add]t), n. & adv.
See {Aught}.

\Ought\, imp., p. p., or auxiliary. [Orig. the preterit of
the verb to owe. OE. oughte, aughte, ahte, AS. [=a]hte.
[root]110. See {Owe}.]
1. Was or were under obligation to pay; owed. [Obs.]
         This due obedience which they ought to the king.
                                               --Tyndale.
         The love and duty I long have ought you. --Spelman.
         [He] said . . . you ought him a thousand pound.
                                               --Shak.
2. Owned; possessed. [Obs.]
         The knight the which that castle ought. --Spenser.
3. To be bound in duty or by moral obligation.
         We then that are strong ought to bear the
         infirmities of the weak.              --Rom. xv. 1.
4. To be necessary, fit, becoming, or expedient; to behoove;
   -- in this sense formerly sometimes used impersonally or
   without a subject expressed. ``Well ought us work.''
   --Chaucer.
         To speak of this as it ought, would ask a volume.
                                               --Milton.
         Ought not Christ to have suffered these things?
                                               --Luke xxiv.
                                               26.
Note: Ought is now chiefly employed as an auxiliary verb,
      expressing fitness, expediency, propriety, moral
      obligation, or the like, in the action or state
      indicated by the principal verb.
Syn: {Ought}, {Should}.
Usage: Both words imply obligation, but ought is the
       stronger. Should may imply merely an obligation of
       propriety, expendiency, etc.; ought denotes an
       obligation of duty.