adulterous (adj.) Look up adulterous at Dictionary.com
c. 1600, a classical correction (replacing earlier avoutrious "addicted to adultery," c. 1400), from obsolete verb adulter (see adulterer) + -ous. Related: Adulterously. Adulterine (1640s, from Latin adulterinus) was used in the sense "pertaining to adultery, born of adultery."