Antonyms of adj reactionist

1 sense of reactionist

Sense 1
reactionary, reactionist, far-right -- (extremely conservative)

INDIRECT (VIA center, right) -> left -- (of or belonging to the political or intellectual left)
INDIRECT (VIA right, left) -> center -- (of or belonging to neither the right nor the left politically or intellectually)

Similarity of adj reactionist

1 sense of reactionist

Sense 1
reactionary, reactionist, far-right -- (extremely conservative)
       => right (vs. left) (vs. center) -- (of or belonging to the political or intellectual right)