'Adulterous' in the Bible

But He replied and said to them, “An evil and adulterous generation [that is morally unfaithful to God] craves and demands a [miraculous] sign; but no sign will be given to it except the sign of the prophet Jonah;

For whoever is ashamed [here and now] of Me and My words in this adulterous and sinful generation, the Son of Man will also be ashamed of him when He comes in the glory of His Father with the holy angels.”

Marriage is to be held in honor among all [that is, regarded as something of great value], and the marriage bed undefiled [by immorality or by any sexual sin]; for God will judge the sexually immoral and adulterous.

But as for the cowards and unbelieving and abominable [who are devoid of character and personal integrity and practice or tolerate immorality], and murderers, and sorcerers [with intoxicating drugs], and idolaters and occultists [who practice and teach false religions], and all the liars [who knowingly deceive and twist truth], their part will be in the lake that blazes with fire and brimstone, which is the second death.”