The phrase 'sitting tight' means to remain in a position, typically for a prolonged period. Synonyms for 'sitting tight' include being patient, awaiting, staying put, staying patient, holding on, waiting it out, and biding time. Another synonym is 'holding the fort' which is often used in the context of someone staying in place while others are away. Similarly, 'staying the course' means to persist in a goal or plan despite obstacles. 'Standing firm' is another synonym, indicating a steadfast commitment to a specific position or belief. Overall, there are many ways to express the concept of being patient and remaining in a particular place or situation, each with slightly different connotations.