Half-pint is a term used to describe a small or diminutive person, specifically a child. Antonyms for the word half-pint would include terms such as adult, giant, or full-grown. These antonyms are often used to describe a person who is fully developed into adulthood and is not considered small or young. Other antonyms for half-pint could include terms such as mature, developed, or grown-up. Regardless of the antonym used, the term half-pint specifically refers to a person of small stature, often with a youthfulness or immaturity associated with their size.