The phrase "sat back" implies a state of relaxation or passivity. Some synonyms for this phrase include reclined, lounged, relaxed, rested, slouched, and laid back. Each of these words suggests a similar sense of ease and leisure, indicating a lack of urgency or engagement. Alternatives like leaned back, propped up, stretched out, or settled in could also be used to describe a comfortable position. Depending on the context, other words like observed, watched, surveyed, or monitored could also convey the idea of sitting back without the physical posture. Overall, there are many options for expressing the concept of sitting back in various ways.