In Old English and occasionally in Middle English used to express necessity of various kinds (for the many shades of meaning in Old English see…

Expressing necessity or obligation: am (is, or are) obliged to, have (or has) to, must. Frequently with need or needs. With infinitive. Obsolete.

Expressing necessity: am (is, are) obliged or required to; have (has) to; it is necessary that (I, you… With following infinitive.

= Must (by moral obligation, logical or natural necessity).

= must, v.1 3a.

intransitive. Originally Scottish and English regional (northern); now chiefly Law. With passive infinitive: to need to be done. Less commonly…

To be under a necessity or obligation to do something; = have, v. 42. transitive. In affirmative declarative clauses and in interrogative clauses.