The antonyms for "stick in to" are "abandon," "give up," "let go," "relinquish," "surrender," and "yield." These words imply a lack of persistence or commitment to a task or goal. Abandoning an idea or plan is like admitting defeat, while giving up signifies a lack of willpower or determination. Relinquishing something means to release or surrender control, while yielding denotes conceding defeat to something or someone. Overall, antonyms for "stick in to" reflect a lack of passion, dedication, and perseverance, all of which are essential for success in any endeavor.