Q: if something is trademark, can it be use if you show that it is trademark for a business purposes

A: Trademarks (for goods) and service marks (for services) are used for identifying the "source" of the goods/services. Business names sometimes are referred to as trade names.

Your question is a little unclear. If you are asking whether a business name can also be used as a trademark, yes. Apple is the name of a company, and Apple is also the trademark of that company's particular brand of smart phone.

If you're asking whether you can use a word or phrase for your business name that is already someone else's trademark, the answer is "maybe." Every situation is different. There are a lot of factors to be considered, such as the goods/services of the mark in question, the fame of the mark, the underlying business of the company that wants to use the trademark as a trade name, etc. For instance, if "Acme" is an existing mark used with running shoes, and if someone now wants to use "Acme" as the name of their company that does home repairs, there might not be an issue. But if someone wants to use a famous mark like "Google" for their new private investigator service, Alphabet Inc. (which owns "Google") might object.

It's best to consult with a trademark attorney to consider individual facts before choosing a mark or using someone else's established mark for a new business name.

A: You should definitely consult an attorney

IF you are only making reference to the brand, such as mentioning that "Nike is a good company to work for, and are good shoes" then you may be ok.

If it is trying to make people believe you are endorsed by the brand or your product is endorsed by them, then you are in trouble.