"Gat in there" is an informal phrase commonly used to encourage someone to take action or push through a difficult task. Synonyms for this phrase include "go for it," "just do it," "give it your all," "put your back into it," and "go the distance." These phrases all express a sense of urgency and determination, urging the listener to give their best effort and not hold back. While they may differ slightly in tone or emphasis, they all share a similar message: don't hesitate or falter, but instead face the challenge head-on with confidence and perseverance.