“Six-pack” muscles, informally

ABS

Not available

The clue refers to the slang term for abdominal muscles, which are often called a "six-pack" because well-defined abs can resemble the shape of a six-pack of beverages. "Informally" signals that the answer is a casual or shortened version of the word, not the full term "abdominals." That’s why the answer is simply "ABS," the common shorthand for these muscles.