What is the meaning of Abstain?

Keep or withhold oneself.

Refrain from (something or doing something); keep from doing, especially an indulgence.

Fast (not eat for a period).

Deliberately refrain from casting one's vote at a meeting where one is present.

Hinder; keep back; withhold.

to abstain (to deliberately refrain from casting one's vote at a meeting where one is present)

to abstain (to fast, diet)

Source: wiktionary.org