In Korean there is a very simple way to make an adjective.
DV + (ㄴ/은)
1.You take a descriptive verb, remove the ‘다’ base, and if it ends in a vowel, you add ㄴ to the bottom, and if it ends in a consonant, you append 은, and place it in front of the noun you want to describe. That’s it.
작다 = to be small. 작 + 은 = 작은 = small.
행복하다 = to be happy. 행복하 + ㄴ = 행복한 = happy.
예쁘다 = to be pretty. 예쁘 + ㄴ = 예쁜 = pretty.
DV + 운
2. For verbs that end in ‘ㅂ’, you remove the ‘ㅂ’ and append ‘운’ instead.
아름답다 = to be beautiful. 아름다 + 운 = 아름다운 = beautiful.
N + 적 + 인
3. You might see the word ‘적’ attached to some nouns. This is the equivalent of adding ‘-ness’ to a noun, but to make it actually modify a noun, you have to append ‘인’ in addition to ‘적’.
사교적인 = 사교 (social) + 적 (social-ness) + 인 = sociable.
예쁜 여자 있어요! = There’s a pretty girl!
그는 진짜 조용한 사람이에요. = He’s a really quiet guy.
For a list of common descriptive verbs, there’s a list here.
DV + (아/어/여)지다
3. Attaching (아/어/여)지다 to a descriptive verb (adjective) means ‘to become + DV’.
예뻐졌어요! = (It) became prettier!