The word "more activating" implies an increase in energy and stimulation. Its antonyms, or opposite words, are those that suggest a decrease or absence of such qualities. Some antonyms that come to mind include "calming," "relaxing," "sedative," "tranquil," and "soothing." These words connote a sense of peacefulness and stillness, as opposed to heightened activity or excitement. Other antonyms may include "dull," "boring," "lackluster," or "uninspiring." It's worth noting that the antonyms for "more activating" vary depending on context, and can include words from different levels of energy or intensity.