Oust, v. t. [imp. & p. p. Ousted; p. pr. & vb. n. Ousting.]
Etymology: [OF. oster, F. ôter, prob. fr. L. obstare to oppose, hence, to forbid, take away. See Obstacle, and cf. Ouster.]
1. To take away; to remove. Multiplication of actions upon the case were rare, formerly, and thereby wager of law ousted. Sir M. Hale.
2. To eject; to turn out. Blackstone. From mine own earldom foully ousted me. Tennyson.
1 other Webster entry under this spelling
Oust, n.
See Oast.
Shades of meaning
Fernald has no entry of its own for oust; he lists it under banish.
He lists it without comment; the entries above explain its neighbors.