Antonyms for Increase (opposite meaning)
WordNet sense 1 (a process of becoming smaller or shorter):
decrease, decrement, decreaseWordNet sense 2 (a change downward):
drop-offWordNet sense 3 (the act of decreasing or reducing something):
diminution, reduction, step-downWordNet sense 4 (decrease in size, extent, or range):
diminish, fallFrom the ODE community, based on WordNetadd/edit