Emily Dickinson Lexicon

OUGHT, v. [imperfect. aut. This word seems to be the preterit tense of the original verb to owe, that is, Sax. agan, Goth. aigan, Sw. äga, to have or possess, the radical sense being to hold, to restrain or stop; hence the passive participle would signify held, bound. In this sense it was used by Spelman and Dryden. But ought as used, is irregular, being used in all persons both in the present and past tenses; as, I ought, thou oughtest, he ought; we, ye, they ought.]

1. To be held or bound in duty or moral obligation. These ought ye to have done, and not to leave the other undone. Matth. xxiii. We that are strong ought to bear the infirmities of the weak. Rom. xv. Thou oughtest therefore to have put my money to the exchangers. Matth. xxv.
2. To be necessary; to behoove. Ought not Christ to have suffered these things and to enter into glory? Luke xxiv.
3. To be fit or expedient in a moral view. My brethren, these things ought not so to be. James iii.
4. As a participle, owed; been indebted to. The love and duty I long have ought you. Spelman. That followed, sir, which to myself I ought. Dryden. [In this sense, obsolete.]
5. In Chaucer's time, it was used impersonally. “Wel ought us werke,” that is, well it behooveth us to work.