The word "un-heedful" implies a lack of attention or care towards something. Its antonyms would therefore be words that describe a state of attentiveness or mindfulness. Some possible antonyms for "un-heedful" include attentive, mindful, observant, vigilant, cautious, wary, attentive, alert, conscious, and watchful. These words all suggest a state of being fully present and aware of one's surroundings or of a particular situation, indicating a willingness to listen to others and to take note of what is happening around them. By being mindful and attentive, we increase our ability to respond effectively to the needs of those around us and to make informed decisions that benefit us and those we care about.