(especially of a man) to have many casual sexual encounters or affairs, especially when married or in a committed relationship.

What does Philander mean?

intransitive verb. : to have casual or illicit sex with a person or with many people especially : to be sexually unfaithful to one's spouse —usually used of a man … her philandering brother-in-law; and … the schoolteacher he philanders with. —

What does it mean if someone is promiscuous?

1 : having or involving many sexual partners : not restricted to one sexual partner or few sexual partners. 2 : not restricted to one class, sort, or person : indiscriminate education … cheapened through the promiscuous distribution of diplomas— Norman Cousins. 3 : casual, irregular promiscuous eating habits.