"Yucky" is a modern, colloquial English word with a transparent and playful origin. It derives directly from the exclamation "yuck," which emerged in the 1960s as an expressive sound conveying disgust or revulsion. By adding the productive adjectival suffix "-y," the interjection was transformed into a descriptive term meaning "disgusting" or "unpleasant." This pattern of creating informal adjectives from expressive sounds (e.g., "icky," "goody") is a common feature of English, showcasing the language's capacity for onomatopoeic and affective word formation outside of classical etymological lineages.

The word is a simplex formation. It is a playful, informal coinage based on the interjection "yuck" (expressing strong distaste), combined with the adjectival suffix "-y". The suffix "-y" is from Middle English "-y", "-i", from Old English "-iġ", used to form adjectives meaning "characterized by" or "full of".