The antonyms of the word 'banked up' are dispersed, emptied, reduced, and decreased. When something is dispersed, it is spread out or scattered, rather than being accumulated or piled up. Emptied means the opposite of being filled or stocked up, suggesting that something has been emptied out or drained. Reduced means to decrease or lessen something in size, amount or value as opposed to increasing or building up. Finally, decreased signifies something getting smaller or lessened compared to being enlarged, amassed or banked up. Understanding these antonyms may prove useful when you need to convey the opposite of 'banked up' in a particular context.