Indexing content and synonyms for a search engine -

I am developing a search engine.

I am thinking about unique words,

"fast and powerful laptop"

will get the following results ...

Of course, the other words with "fast and powerful laptops" and "quick-capable netbook"

synonyms will not be displayed to the user, but only to create search results Will be used to help more relevant.

What do you think about this idea? What are the disadvantages you see? Does anyone do this?

In the end the search must be blotted with multiple synonyms if you have 5 words, then each There are 10 identical words, now you are searching about 50 words.