n. The maximum: The car can seat five adults, but that's the max. adj. Maximal.ad. Maximally: We'll pay $250 max. verb-intransitive. To reach one's limit, as of endurance or capability: The weightlifter maxed out at 180 kilograms. verb-intransitive. To reach a point from which no additional growth, improvement, or benefit is possible: The salary for this position maxes at $45,000.