noun which may take the genitive case particle 'no', noun
philandering nature; flirtatious disposition
Describes a person's inherent tendency to be unfaithful or flirtatious, often used as a noun or with の to modify another noun.
彼の浮気性には本当に困っている。
I'm really troubled by his philandering nature.
浮気性の人は長続きしない。
People with a flirtatious disposition don't last long in relationships.
浮気 refers to the act of cheating or being unfaithful, while 浮気性 describes the personality trait of being prone to such behavior.
Compound of 浮気 (うわき, 'unfaithfulness') and 性 (しょう, 'nature/tendency'). The variant 浮気症 uses 症 (しょう, 'symptom/condition'), suggesting a more pathological nuance.