ngoài khơi 
off the coast of, offshore [ ngoài ] : besides, outside, aside from, in addition; without, exterior, external; up north (referring to the northern part of VN)
[ khơi ] : to enlarge, widen; open sea
Most Common Compounds Set 1:
Most Common Compounds Set 2 :
mỏ dầu ngoài khơi offshore oil well ra đánh cá ngoài khơi to go fishing off-shore