Definition of Abstemious

Abstemious: Marked by restraint, especially in the consumption of food or alcohol.
From the Latin prefix "abs-," meaning "from" or "away," and the Latin noun "temetum," meaning "intoxicating drink."

Definition of Abscission

Abscission: To remove tissue by cutting it
away, as in surgery.

Definition of Ab-

Ab-: Prefix meaning "from, away from, off" as in abduction (movement of a limb away from the midline of the body), ablate (carry or cut away), abnormal (away from normal), absorb (to suck away). Ab in Latin means "from."
"Abs" in the plural is commonly used slang for the abdominal muscles.