거리 = something...
마실거리 = 마시다 + ㄹ(make 마시다 adjective) + 거리 = something to drink.
There are only two commonly used words made with 거리
마실거리 = something to drink, a drink
먹을거리 = something to eat, so food
not commonly used but 놀거리 means something to enjoy, 읽을거리 means something to read.. and so on.