This is just guesswork.这只是猜测。

This isn't just guesswork. I know someone was in the house.这可不只是猜测, 我知道有人在房子里。

Who did it is a matter of guesswork.谁干的这件事, 人们还在猜测。

The question of who planted the bomb remains a matter of guesswork.谁埋的炸弹这个问题至今还是个谜。

I got the answer by guesswork.我通过猜测得出了答案。