Definition of "eft"

Only these marishes and myrie bogs, / In which the fearefull ewftes do build their bowres, / Yeeld me an hostry mongst the croking frogs […].

1596, Edmund Spenser, “Book V, Canto X”, in The Faerie Queene. […], London: […] [John Wolfe] for William Ponsonbie

How did he like it when the live creatures / Tickled and toused and browsed him all over, / And worm, slug, eft, with serious features / Came in, each one, for his right of trover?

1844, Robert Browning, "Garden Fancies," II. Sibrandus Schafnaburgennis

And when they were all gone, / And the dim moon doth eft withhold the light, […]

1557, Henry Howard, Earl of Surrey, The Fourth Book of Virgil