There are many synonyms for the phrase "quiet ecstasy", which can be used to describe a state of bliss or happiness accompanied by a peacefulness or serenity. Some possible synonyms might include "tranquil joy", "silent rapture", "calm euphoria", "serene bliss", "peaceful elation", or "still exultation". These phrases all suggest a sense of contentment and pleasure, but also highlight the quiet, introspective nature of the emotion. Whether you are enjoying a quiet moment alone, or simply feeling at peace with the world around you, these synonyms can help you express the unique feeling of quiet ecstasy.