The antonym for the word "head-long" can be described by various words such as cautious, hesitant, slow, and deliberate. These words explain a behavior or action that is not done rapidly or without care. Instead, individuals who show these characteristics might display a thoughtful approach or an action that is carefully thought out. Therefore, if someone is not acting headlong, they are displaying a sense of mindfulness, showing a measure of patience that helps avoid unforeseen and sometimes unpleasant consequences. As such, being cautious, slow, or deliberate can sometimes lead to a more successful outcome than rushing headlong into an action without giving it due thought.