The phrase "fall headlong" refers to falling suddenly and violently, often resulting in injury. Antonyms for this phrase would involve not falling or falling in a controlled and safe manner. Words like "ascend," "climb," and "rise" would indicate moving upward or in a positive direction. Other options might include "descend" or "lower oneself," which would involve moving downward but with care and control. "Jump" or "leap" might also be appropriate antonyms, indicating intentional and controlled movement rather than a sudden, uncontrolled fall. Overall, antonyms for "fall headlong" would involve moving carefully, deliberately, and with intention, rather than experiencing a sudden, accidental fall.