'Unnatural' in the Bible

This is why God delivered them over to degrading passions. For even their females exchanged natural sexual relations for unnatural ones.

Do you not know that unrighteous men will not inherit God's Kingdom? Cherish no delusion here. Neither fornicators, nor idolaters, nor adulterers, nor any who are guilty of unnatural crime,

For those who go after loose women, for those with unnatural desires, for those who take men prisoners, who make false statements and false oaths, and those who do any other things against the right teaching,

So also Sodom and Gomorrah and the neighboring towns, since they indulged in sexual immorality and pursued unnatural desire in a way similar to these angels, are now displayed as an example by suffering the punishment of eternal fire.