Ugliness is considered to be the opposite of beauty.
The experience of "beauty" often involves an interpretation of some entity as being in balance and harmony with nature, which may lead to feelings of attraction and emotional well-being. Because this can be a subjective experience, it is often said that "beauty is in the eye of the beholder."
There is evidence that perceptions of beauty are evolutionary determined, that things, aspects of people and landscapes considered beautiful are typically found in situations likely to give enhanced survival of the perceiving human's genes.
The classical Greek noun that best translates to the English-language words "beauty" or "beautiful" was κάλλος, kallos, and the adjective was καλός, kalos. However, kalos may and is also translated as ″good″ or ″of fine quality″ and thus has a broader meaning than mere physical or material beauty. Similarly, kallos was used differently from the English word beauty in that it first and foremost applied to humans and bears an erotic connotation.
The Koine Greek word for beautiful was ὡραῖος, hōraios, an adjective etymologically coming from the word ὥρα, hōra, meaning "hour". In Koine Greek, beauty was thus associated with "being of one's hour". Thus, a ripe fruit (of its time) was considered beautiful, whereas a young woman trying to appear older or an older woman trying to appear younger would not be considered beautiful. In Attic Greek, hōraios had many meanings, including "youthful" and "ripe old age".