The phrase "sucked up to" implies a sense of insincerity and flattery, often used to describe people who are trying to gain favor or win someone over. However, there are many antonyms for this phrase that can be used to convey a more positive or genuine approach. Some examples include acting with integrity, being honest, speaking truth to power, standing up for oneself, and demonstrating loyalty. By using these alternatives, you can effectively express yourself without resorting to flattery or manipulation, and build more authentic connections with the people around you.