After he won the amateur championship he turned professional.

他获得业余赛冠军后就转为职业运动员了。

《牛津词典》

He was apparently much surprised at the news that the amateur athlete beat the professional one who ranked top ten.

他显然对那位业余运动员击败了排名前十的职业运动员的事实感到非常惊讶。

youdao

Jerry is an amateur who dances because he feels like it.

杰瑞是一位业余舞蹈爱好者，他跳舞因为他喜欢跳。

《柯林斯英汉双解大词典》

Now, and I don't think this is unimportant, King was also - it would seem he was also a minor poet, an amateur poet.

我认为这并非不重要，金也是,-尽管不显赫，他也是个诗人，一个业余诗人。

耶鲁公开课 - 弥尔顿课程节选

Having been around horses all his life - his father was a former leading Irish amateur - it came as no surprise when he became Irish amateur champion.

BBC: SPORT | Other Sport | Horse Racing | Timmy Murphy

He was an amateur bee keeper but now does it on a more commercial basis.

BBC: Making a bee-line for city roofs

He outed himself as an amateur chef 10 years ago, when he put a hidden video of him in the kitchen on a CD.

NPR: 'Peace, Happiness' and G. Love