“竞争激烈的”用英语表达可以是“very competitive”，还有一个很形象的表达方式 dog eat dog 或 dog-eat-dog，字面意思是“狗吃狗”，还可以译为“残酷无情的”，寓意：

1、a very competitive world
竞争激烈的世界

2、ruthlessly competitive business environment
残酷竞争的商业环境

3、marked by destructive or ruthless competition; without self-restraint, ethics, etc.
以破坏性的或残酷的竞争为特点的；没有自制力、道德等的

4、do anything to be successful, even if what they do harms other people
做任何事都要成功，即使他们的所作所为伤害了别人

解析：even if 引导的从句是往往是假设性的，相当于汉语的“即使”“纵然”“就算”“哪怕”。

5、getting ahead in life at any cost
不惜一切代价在生活中出人头地

6、a place or situation that is highly competitive
竞争激烈的地方或环境

例如：

1、The only rule of the marketplace was dog-eat-dog.
市场上唯一的规则就是激烈的竞争。

2、It's a dog-eat-dog industry.
这是一个竞争残酷的行业。

3、You have to look out for your own interests; it's a dog-eat-dog world.
你得为自己的利益着想，这是一个竞争激烈的世界。

解析：短语动词 look out for sb/sth 的其中一个意思是“当心；提防；留心防备”，相当于 watch out.

4、Your company fired you two days after you had a heart attack? Well, it's certainly a dog-eat-dog world.
你的公司在你心脏病发作两天后解雇了你？嗯，这真是一个残酷无情的世界。

5、It's a dog eat dog world out there. You have to do whatever you can to survive.
外面是一个竞争激烈的世界。为了生存，你必须尽你所能。

解析：连词代词 whatever 引导的宾语从句。

6、In film business it's dog eat dog. One day you're a star, the next you've been replaced by younger talent.
电影界充满了残酷无情的竞争。前一天你成了明星，下一天你又被年轻的天才所取代。