Abscisic acid is a plant hormone that controls various physiological processes, including seed dormancy, water stress response, and growth inhibition. Its antonyms, or opposite words, refer to hormones that have opposite effects or functions in plants. One antonym is auxin, a hormone that promotes cell elongation, root growth, and apical dominance. Another antonym is gibberellin, a hormone that induces seed germination, stem elongation, and fruit size enlargement. Ethylene, a gas hormone that regulates fruit ripening and senescence, is also an antonym. Finally, cytokinins, which stimulate cell division and differentiation, are antonyms that counteract abscisic acid's inhibitory effects on growth.