Meaning of “abstain” - Learner’s Dictionary

abstain

verb [ I ] us uk /əbˈsteɪn/
NOT DO formal

to not do something that you enjoy because it is bad or unhealthy:

The doctor suggested that he abstain from alcohol.
NOT VOTE

to choose not to vote for or against something:

63 members voted in favour, 39 opposed and 5 abstained.
abstention noun [ C, U ] us uk /əbˈstenʃən/

(Definition of “abstain” from the Cambridge Learner’s Dictionary © Cambridge University Press)