복통이 · 복통을
stomachache, abdominal pain
Example
어제 저녁을 먹고 나서 심한 복통이 생겼어요.
After dinner yesterday, I got a bad stomachache.
Word parts
복 belly+통 pain
Literally 'belly pain'. -통 = pain: 두통, 치통, 복통.
Good to know
복통 is medical; in daily conversation say 배가 아파요.