The quality of being gullible; the state of being easily deceived or tricked.
From 'cullible' plus the abstract noun suffix -ity; 'cullible' itself derives from 'cull' in the sense of 'to trick or deceive,' with possible Scandinavian roots.
This word reveals an older meaning of 'cull'—to trick or deceive someone—that's almost vanished from modern English, surviving only in 'cullibility.'
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