Emily Dickinson Lexicon

DE-FEC'TION, n. [L. defectio. See Defect.]

1. Want or failure of duty; particularly, a falling away; apostasy; the act of abandoning a person or cause to which one is bound by allegiance or duty, or to which one has attached himself. Our defection from God is proof of our depravity. The cause of the king was rendered desperate by the defection of the nobles.
2. Revolt; used of nations or states.