'Yàn sú' (艳俗) is a compound adjective formed from 艳 (yàn), meaning 'bright, showy, or dazzling', and 俗 (sú), meaning 'vulgar, common, or lacking refinement'. Together, they describe something visually striking but in poor taste — overly flashy, gaudy, and lacking subtlety or elegance. It often carries a negative connotation, implying an attempt at attractiveness that backfires due to excess or kitsch.

The term is frequently used to critique visual aesthetics: clothing, interior decor, advertising, or even animal appearances when artificially enhanced (e.g., dyeing pets’ fur). In zoos or pet markets, brightly dyed birds or rabbits may be described as 艳俗 to criticize the unnatural, tasteless presentation. While not inherently tied to animals, it appears in contexts where human modification of animals results in garishness — hence its inclusion under 'Animals' as a contextual usage domain.