"不能违反校纪"用英语可以说成"cannot violate school regulations"。

来源: "违反"是violate的动词形式,意思是"违背、不遵守"。"校纪"是school regulations的意思,指学校规章制度。

一些英文例句和中文翻译:

It is important to follow the school regulations so that we can create a positive and safe learning environment for everyone. (遵守校纪很重要,这样我们才能为所有人创造一个积极和安全的学习环境。)
If you violate the school regulations, you may face discippnary action. (如果你违反校纪,你可能会面临纪律处分。)
It is not allowed to bring weapons to school, as it violates the school regulations. (不允许带武器进校,因为这违反了校纪。)