A poetess is a woman who writes poetry. The word is simply poet plus the old female ending -ess. Though actually, most people now just say poet for a woman or a man. Poetess can sound old-fashioned, and some readers hear it as if being a woman were a special, smaller kind of poet. You will still meet it in older books, and a few people use it on purpose, but in class and in print today poet is the usual, kind choice. The same shift has happened with words like actor, which many people now use instead of actress.

女詩人（現在多直接說詩人；poetess 偏過時，有時還帶性別刻板的味道）