Good at something; skilled; fluent; practiced, especially in relation to a task or skill.
He was a proficient writer with an interest in human nature.
1912: (w), (w), Chapter 5
By constant playing and experimenting with these he learned to tie rude knots, and make sliding nooses; and with these he and the younger apes amused themselves. What Tarzan did they tried to do also, but he alone originated and became proficient.