ought

aux.v.

1. Used to indicate obligation or duty: You ought to work harder than that.
2. Used to indicate advisability or prudence: You ought to wear a raincoat.
3. Used to indicate desirability: You ought to have been there; it was great fun.
4. Used to indicate probability or likelihood: She ought to finish by next week.

Origin:

Origin: Middle English oughten, to be obliged to

Origin: , from oughte, owned

Origin: , from Old English āhte

Origin: , past tense of āgan, to possess; see aik- in Indo-European roots

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Usage Note: Unlike other auxiliary verbs, ought usually takes to with its accompanying verb: We ought to go. Sometimes the accompanying verb is dropped if the meaning is clear: Should we begin soon? Yes, we ought to. In questions and negative sentences, especially those with contractions, to is also sometimes omitted: Oughtn't we be going soon? This omission of to, however, is not common in written English. Like must and auxiliary need, ought to does not change to show past tense: He said we ought to get moving along. • Usages such as He hadn't ought to come and She shouldn't ought to say that are common in many varieties of American English. They should be avoided in written English, however, in favor of the more standard variant ought not to.

verb
Obsolete