Abstention = refusal to vote, abstaining

• In the election to the local council, there were three abstentions.
• There were ten votes in favour, three against and two abstentions.
• Political parties are expecting high levels of abstention in the forthcoming elections.

Abstinence = the practice of restraining oneself from indulging in something, typically alcohol or sex; teetotalism; temperance; self-restraint etc.

• He started drinking after ten years of abstinence.
• She observed two days of abstinence from food and drink as penance for wrongdoing.
• Among birth control methods , abstinence from sex is equally effective as artificial contraceptive devices.
• Abstinence can be resorted to against unwanted pregnancies.