由于不客气一词在中文里有不同的意思，所以对应的英文表达方式也有很多种。

比如对别人表达感谢的回应可以是you're welcome, don't mention it。

当不客气充当不礼貌或者粗鲁的含义时，可以使用单词impolite, rude, blunt等。

当要表达对别人不客气了的意思时，可以使用词组put a flea in one' s ear。

参考例句：

  • He was unkind to you.
    他对你不客气。
  • Do not mention it .
    不客气。
  • Being called by a nickname is not usually uncomplimentary
    被人起了绰号并不一定是不客气
  • Such unkind remark was not called for.
    这种不客气的话真不该讲。
  • The customer was angry with the sales girl for her impolite answer.
    那位顾客对女店员不客气的回答感到忿怒。
  • He addressed me forcibly in the vernacular
    他用下流话对我不客气地说话。
  • Your unkind remark was not called for.
    你这种不客气的话真不该讲。
  • She is rather short with him when he ask for help.
    他请她帮帮忙，她却不客气地把他顶了回去。
  • Don't mention it. You should drink some water and go to lie down.
    不客气，你应该多喝些水，去躺一下。
  • I'll put a flea in his ear if he bothers me once more.
    如果他再来打扰的话，我就要对他不客气了。

you是什么意思：
pron. 你，您；你们，您们；各位，大家

welcome是什么意思：
v. 欢迎，款待，愉快的接受，迎接
n. 欢迎，迎接，接受；欢迎辞
adj. 受欢迎的，令人愉悦的，不受限制的
int. 欢迎

  • Welcome you to the fair.
    欢迎您到交易会来。
  • Whomever you invite will be welcome.
    你邀请的任何人都将受欢迎。
  • A constant guest is never welcome
    常客令人厌

impolite是什么意思：
adj. 失礼的，粗鲁的

  • Don' t be impolite to her ! 
    不要对她没礼貌！
  • He was scourged for his impoliteness.
    他的无礼举止受到了严厉的批评。
  • It is impolite to poke the top of food with chopsticks.
    用筷子戳食物项端是不礼貌的。