5 bread is a quirky way of saying oppang. 5 bread as a direct translation in Korean would be 오 빵 (oh-ppang) which is a play on words. The word 오빠 (oppa) is the korean word for brother but adding the ng ending (ㅇ) is a way that some females use to sound more cutesy or flirt.
"5 breaddd~ you're so cooll."
by ammby13 June 14, 2021