Abstain means,
To hold yourself back from; to keep yourself from. ('Abstain' is a word used
mainly when talking about the passions, appetites, or sinful indulgences.)

For this is the will of God, even your sanctification, that you should abstain from fornication; that every one of you should know how to possess his vessel in sanctification and honour; not in the lust of concupiscence, even as the Gentiles which know not God. 1 Thessalonians 4:3-5