The quality or state of being extremely light, thin, and delicate like gossamer.
From gossamer + the suffix -iness (forming nouns that express qualities or conditions), creating an abstract noun describing the degree of delicacy and transparency.
The word 'gossameriness' needs four syllables to express what 'gossamer' does in one—it's like the word is itself becoming heavier and more cumbersome as it tries to describe something impossibly light, which is kind of poetic.
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