Colour-emotion association data show a universal consistency in colour-emotion associations, apart from emotion associations with PURPLE. Possibly, its heterogeneity was due to different cognates used as basic colour terms between languages. We analysed emotion associations with PURPLE across 30 populations, 28 countries, and 16 languages (4,008 participants in total). Crucially, these languages used the cognates of purple, lilac, or violet to denote the basic PURPLE category. We found small but systematic affective differences between these cognates. They were ordered as purple > lilac > violet on valence, arousal, and power biases. Statistically, the cognate purple was the most strongly biased towards associations with positive emotions, and lilac was biased more strongly than violet. Purple was more biased towards high power emotions than violet, but cognates did not differ on arousal biases. Additionally, affective biases differed by population, suggesting high variability within each cognate. Thus, cognates partly account for inconsistencies in the meaning of PURPLE, without explaining their origins.