屠龙之技的英文：
[Literal Meaning]
slaughter/dragon/aux./art
the art of killing dragons

[解释]
毫无实用价值。

[Explanation]
meaning something that has no practical value at all.

[例子]
你这次学的就是屠龙之技，对公司的技术进步没有任何价值。

[Example]
What you learned this time is the art of killing dragons, which will provide no help for the company's development in technology.

To master the skilled-art of slaughtering dragon
屠龙之技