Intempestivity is a word that is rarely used in everyday speech, and it refers to unpredictability or being subject to the whims of the moment. While antonyms would typically refer to the opposite of a word, in the case of intempestivity, antonyms could be seen more as corresponding words that denote predictable or consistent behavior. These antonyms might include traits such as reliability, stability, consistency, or steadfastness. Other possible antonyms might include calmness, tranquility, and serenity, which would all oppose the frantic, unpredictable behavior associated with intempestivity. In summary, antonyms for intempestivity include words that reflect predictability, stability, reliability, and calmness.