Webster's Revised Unabridged Dictionary · 1913

aby

aby , verb

1.
atone for, make amends for

Aby ({not transcribed}) , verb, transitive and intransitive

[Anglo-Saxon ābycgan to pay for; pref. ā- (compare Gothic us-, German er-, orig. meaning out) + bycgan to buy. See Buy, and compare Abide.]

1.
To pay for; to suffer for; to atone for; to make amends for; to give satisfaction. [Obsolete]
Lest to thy peril thou aby it dear. — Shakespeare
2.
To endure; to abide. [Obsolete]
But nought that wanteth rest can long aby. — Spenser

Also: Abye