What does the caotain call macbeht in line 16 Macbeth?

The Captain doesn't actually call Macbeth anything in line 16 of Macbeth. He is simply describing him in a very complimentary way:

"As valiant as the lion, and as bold as the North," (Act 1, Scene 2, Line 16)

He is comparing Macbeth's courage and bravery to that of a lion, and his fierceness to the harshness of the North.

Let me know if you have any other questions about Macbeth or Shakespeare!