Webster's Revised Unabridged Dictionary · 1913

Forego

Forego , transitive verb

[See Forgo.]

1.
To quit; to relinquish; to leave.
Stay at the third cup, or forego the place. — Herbert
2.
To relinquish the enjoyment or advantage of; to give up; to resign; to renounce; -- said of a thing already enjoyed, or of one within reach, or anticipated.
All my patrimony,, If need be, I am ready to forego. — Milton
Thy lovers must their promised heaven forego. — Keble
[He] never forewent an opportunity of honest profit. — R. L. Stevenson

Forgo is the better spelling etymologically, but the word has been confused with Forego, to go before.

Forego , transitive verb

[Anglo-Saxon foregān; fore + gān to go; akin to German vorgehen to go before, precede. See Go, v. i.]

To go before; to precede; -- used especially in the present and past participles.
Pleasing remembrance of a thought foregone. — Wordsworth
For which the very mother's face forewent The mother's special patience. — Mrs. Browning
Collocations (1)
Foregone conclusion , a conclusion which has preceded argument or examination; a predetermined conclusion.