성인이 · 성인을
adult, grown-up
Example
한국에서는 만 열아홉 살부터 성인으로 봅니다.
In Korea, people are considered adults from age nineteen.
Word parts
성 become, complete+인 person
Literally 'a completed person.' Homonym warning: another 성인 means 'saint.'
Good to know
어른 is the everyday word; 성인 is used for legal age, ticket prices and official contexts.
Related words