Having reached the highest point or maximum level; also describes someone looking pale, thin, or sickly.
From peak, ultimately from Spanish pico 'sharp point.' The 'sickly' meaning developed from the idea of someone's face becoming sharp and pointed due to illness, first recorded in the 16th century.
This word brilliantly captures two opposite meanings - the triumph of reaching a summit and the concern of looking unwell. Both meanings share the visual metaphor of sharpness: mountain peaks are sharp points, and illness can make facial features appear sharp and angular.
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