The quality or state of being blissful; supreme happiness or perfect joy.
From 'blissful' (adjective) plus '-ness' (forming abstract nouns indicating a quality or state). This follows the standard English pattern of converting adjectives to nouns of quality.
Adding '-ness' to any adjective creates an abstract noun—it's one of English's most productive word-building tools. 'Blissfulness' is more formal and abstract than just saying 'bliss,' implying you're discussing the quality itself rather than experiencing it.
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