Eft·soon′, Eft·soons′, adv. [OE. eftsone, eftsones; AS. eft + sōna soon. See Eft, and Soon.] Again; anew; a second time; at once; speedily. [Archaic]
And, if he fall from his capel [horse] eftsone. Chaucer.
The champion stout eftsoons dismounted. Spenser.