Condition Subsequent Definition: A condition in a contract that causes the contract to become invalid if a certain event occurs. A condition in a contract or will that causes the contract to become invalid if a certain event occurs. This is different from a condition precedent. The happening of a condition subsequent may invalidate a contract which is, until that moment, fully valid and binding. In the case of a condition precedent, no binding contract exists until the condition occurs. REFERENCES: Re McColgan Estate, 1969 DLR 572 Categories & Topics: Contract Law Dictionary Find you are constantly looking up definitions? Try our search provider (works in most modern browsers) If you find an error or omission in Duhaime's Legal Dictionary, or if you have legal term suggestion, we'd love to hear from you!