Would you consider Sauron a coward?

I was talking to a few people about how I wish Sauron made a few more appearances in the books/movies. Someone said that not only does this make him more mysterious and showcase his hold over the world (which I agree), but it's also a part of his character. Namely, that he is a coward who only fights when he has to.

Given that he waited seven years in Mordor to fight Gil-galad and Elendil, would you say this is an accurate claim?