Abstinence means to voluntarily stop doing some
type of pleasurable activity. In medical terms, the
term is often used to refer to not having intercourse,
not eating a particular food (e.g., junk food), not
drinking alcoholic beverages, or not using illegal
drugs. There are many reasons why people practice
abstinence, singly or in combination. One reason
can be purely health-related such as wanting to
prevent obesity from poor dietary choices or to
prevent diseases from drug use, alcohol use, or
sexually transmitted bacteria/viruses. Another
reason can be due to moral values, religious beliefs,
cultural factors, or family tradition.
The popular "Just Say No"
saying for drug abstinence.
FEATURED BOOK: Abstinence: Members of Overeaters Anonymous Share Their
Experiences (2nd edition).

Abstinence can be permanent, such as a priest or nun’s vow of celibacy or a vegetarian
abstaining from eating meat for the rest of his/her life. However, abstinence is
sometimes temporary such as avoiding certain foods over a specific holiday (e.g.,
fasting) or avoiding sexual intercourse until marriage. For alcoholics, abstinence is often
referred to as sobriety or being sober. Drug addicts who are abstinent from drug use
often refer to this as “being clean.” There are some people, such as workaholics, who
abstain from any other pleasurable activities besides the pleasure derived from work. 
Abstinence comes from the Latin word "abstineo" meaning "to hold back.”
"Where Medical Information is Easy to Understand"™