The term remittable means something that is capable of being remitted or sent back. Therefore, antonyms for the word "more remittable" can refer to characteristics and properties that make something difficult to remit or send back. Some antonyms for remittable could include words like immovable, fixed, irremovable, non-returnable, and unremovable. These terms all describe something that cannot be easily moved or sent back, and therefore, are opposite in meaning to the concept of remittable. Such characteristics could apply to physical objects, assets, and finances, and may be used in a variety of contexts like legal proceedings or financial transactions.