Clause that provides that the failure of a contract party to exercise a right under a contract when an opportunity to do so first arises, does not preclude the invoking of that right at a later date, because of claimed acquiescence. For example, a clause that says that should the other party breach the terms of the agreement and the holder of the right does not sue, cancel the agreement or use any other remedies, it can still at any point choose to do so (i.e. it has not waived its rights) and it may also exercise the rights in the event of a repeated breach of the same type.
Strict no-waiver clauses are common in financing agreements, to protect the lender. They can be problematic in ongoing commercial and development agreements where plans may be frequently changed and so care should be taken when using Boiler Plate clauses..