Eupnoea refers to normal or easy breathing. However, there are several other synonyms for it that can be used in its place. One such synonym is "normal respiration," which refers to the standard amount of airflow in and out of the lungs. Another synonym is "unobstructed breathing," which implies that the airways are not blocked or restricted in any way. Additionally, "regular breathing" can be used to describe the consistent and rhythmic inhalation and exhalation of air. "Peaceful breathing" and "calm respiration" are also synonyms for eupnoea that suggest a relaxed and stress-free state while breathing. Overall, there are various synonyms for eupnoea to describe normal and comfortable breathing.