What do you think of me using the word retarded?
I hope you're joking. Why do you want to use that word?
It's an efficient word to discourage the uncool people
That is not a word you should be using. It is offensive and derogatory toward other people.
You're right, maybe I can put it in a sentence to make it less offensive.
Don't use the word at all. It is abusive to use it and you don't want people to think you are a mean person.