'Expert' in the Bible

They all handle the sword, and are expert in war. Every man has his sword on his thigh, because of fear in the night.

For, behold, I will stir up and cause to come up against Babylon a company of great nations from the north country; and they shall set themselves in array against her; from there she shall be taken: their arrows shall be as of an expert mighty man; none shall return in vain.

especially because you are expert in all customs and questions which are among the Jews. Therefore I beg you to hear me patiently.