early 15c., "well-deserved, merited," from Old French condigne "deserved, appropriate, equal in wealth" and directly from Latin condignus "wholly worthy," from assimilated form of com "together, altogether" (see con-) + dignus "worth (n.), worthy, proper, fitting" (from PIE root *dek- "to take, accept").
In Middle English of rewards as well as punishment, censure, etc., but by c. 1700 used exclusively of punishments, "deservedly severe." Related: Condignity; condignly.