The opposite of increase is decrease or reduce.
increase
Decremental... meaning 'decrease'.
The opposite would be to degrade, lessen, diminish, decrease, or reduce.
contract, decrease, diminish.
I'd say a "drastic decrease".
The opposite of acceleration is, Deceleration.
shrink, decrease in size, reduce
KK
The opposite actually..it increases.
The opposite of build (assemble) is to demolish or disassemble. The opposite of build (raise, increase) would be to decrease, lower, or reduce.
Decrease, Decline, Reduce and Deminish... Hope that Helps...