意思不同：

1.polite意思：adj. 有礼貌的; 客气的; 儒雅的; 应酬的; 礼节性的; 客套的; 上流社会的;

2、courtesy意思：adj.免费乘坐(或使用)的

相关介绍

例句：

The manager of the hotel was courtesy itself.

旅馆经理彬彬有礼。

It's only common courtesy to tell the neighbours that we'll be having a party.

告诉邻居我们要举行聚会，这是起码的礼貌。

例句：

It is not polite of you to cut the speaker short.

你打断发言者的话,真不礼貌。