Scrabble?! INDEFEASIBLY

Definitions of INDEFEASIBLY in various dictionaries:

Indefeasible right of use (IRU) is a permanent contractual agreement, that cannot be undone, between the owners of a communications system and a customer of that system. The word "indefeasible" means "not capable of being annulled, or voided, or undone." The customer purchases the right to use a certain amount of the capacity of the system, for a specified number of years. IRU contracts are almost always long term, commonly lasting 20 to 30 years. The communication system can be a wire cable, such as submarine communications cable, or a fiber optic cable, or a satellite. Depending on the type of system the customer might be buying exclusive use of one, or more, wires in a wire cable, fibers in a fiber optic cable, or channels through a satellite. An IRU owner can unconditionally and exclusively use the relevant capacity of the IRU grantor’s network for the specified time period. These contracts obligate the purchaser to pay a portion of the operating costs, and the costs of maintaining the cable, including any costs incurred repairing the cable after mishaps. The right of use is indefeasible, so the capacity purchased is also nonreturnable, and maintenance costs incurred become payable and irrefusable.