The quality or state of being somewhat coy or mildly shy and evasive.
From 'coyish' plus the suffix '-ness', which forms abstract nouns describing qualities or states. Ultimately derived from Old French 'coi'.
English lets us add '-ness' to almost any adjective to turn it into a noun describing that quality—'coyishness' captures that feeling of being sort of shy but not entirely committed to it.
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