noun which may take the genitive case particle 'no'
Medical term used to describe a condition, disease, or effect that arises as a consequence of another primary condition.
Secondary hypertension occurs due to a specific disease.
This symptom is secondary, and treatment of the underlying disease is necessary.
二次的 is a more general adjective meaning 'secondary' or 'subordinate' in various contexts, while 二次性 is specifically a medical term.
Compound of 二 (ni, 'two, second') + 次 (ji, 'next, order') + 性 (sei, 'nature, -ity'). The term follows the pattern of medical adjectives ending in 〜性.