지내다
jinaeda · TOPIK 1
to get along, to spend time
지나다 (to pass) + 이 = 지내다: to make time pass, so to spend it
지내다 is the causative of 지나다, to pass by. You make the days pass, which is spending time, and how you pass them is how you are getting along. Hence 잘 지내요? = are you passing your days well?