The phrase "plug away" suggests a persistent, steady effort towards a specific task or goal. However, there are several antonyms for this phrase that connote a different attitude and mindset. One antonym is "give up," indicating a complete abandonment of the task or goal. Another antonym is "slack off," which suggests a lack of motivation or discipline. "Procrastinate" is also an antonym for "plug away," meaning to delay or postpone action. Finally, "skimp" is another antonym, meaning to do something with minimal effort or resources. Understanding these antonyms can help individuals recognize when they are not putting in the necessary effort and encourage them to take action towards achieving their goals.