Etymology From Middle English forthy, from Old English forþȳ, for þȳ þe, forþon (“because, since”), from for + þȳ, þon (“by that, therefore”), instrumental case of þæt (“that”); Cognate with Yola farthoo (“why”), Old Norse fyrir því (at) (Danish & Norwegian fordi (“because”), Swedish för att). More at for, the, that.
Forthy as now, I purpose for to wryte... Forthy as now schortlie to conclude.c. 1480, Robert Henryson, The Taill of Schir Chanticleir and the Foxe:
2
Obsolete For this, for this reason; on this account.
Thomalin, have no care for-thy.1579, Immeritô [pseudonym; Edmund Spenser], “May. Ægloga Quinta.”, in The Shepheardes Calender: […], London: […] Iohn Wolfe for Iohn Harrison the yonger, […], →OCLC:
forthy
conj
Etymology From Middle English forthy, from Old English forþȳ, for þȳ þe, forþon (“because, since”), from for + þȳ, þon (“by that, therefore”), instrumental case of þæt (“that”); Cognate with Yola farthoo (“why”), Old Norse fyrir því (at) (Danish & Norwegian fordi (“because”), Swedish för att). More at for, the, that.