When looking for synonyms for "is quiet," there are a plethora of options to choose from. "Silent" denotes complete absence of sound, while "calm" suggests a state of tranquility or serenity that may not necessarily be completely silent. "Hushed" implies a lowered voice or a subdued atmosphere, while "muted" suggests a dampening or reduction in sound. "Peaceful" evokes feelings of ease and contentment and can be applied to both silence and low-level noise. "Solemn" refers to a deeply serious or sober atmosphere and may be used to describe a quiet environment, whether intentional or not. Ultimately, the synonym chosen depends on the context and tone of the situation.