The most common Korean word for “older brother” is 형 (hyeong). There is one more word with a similar meaning — compare them below. 「older brother」는 한국어로 형.
older brother
TOPIK 1 · noun · honorific: 형님
older brother (for females)
TOPIK 1 · noun
Words and levels: TOPIK I essentials (National Institute of Korean Language standard curriculum, KOGL Type 1) · examples: Cheesepotato