병역이 · 병역을
military service
Example
한국에서는 건강한 남성이라면 병역의 의무가 있습니다.
In Korea, healthy men have a duty to do military service.
Word parts
병 soldier+역 duty, service
Literally 'soldier duty'.
Good to know
Usually heard in set phrases like 병역의 의무 (duty of military service) and 병역 면제 (exemption).