I know for me I usually say whatever in a condescending way or to let someone know that I really don't care what they're saying. I know this isn't an attitude of someone who believes and follows Christ. The Bible gives us the perfect definition of the word 'whatever' in Philippians 4:18~
Finally, brothers and sisters, whatever is true, whatever is noble, whatever is right, whatever is pure, whatever is lovely, whatever is admirable—if anything is excellent or praiseworthy—think about such things.
The Spirit has led me to this verse today and forced me to drink. It's really easy for us to think on the negative things of this world. God knew this would be a challenge for us, that's why he gives us many things to hold on to for comfort and hope; this is one of them. If we keep our mind on what is true, noble, right, pure, lovely, admirable, and praiseworthy God tells us that His peace will be with us, v9. What more could we want?
My challenge to you is to start using this word in a new way. Give it the meaning from Phil 4:8. Memorize this verse, put it in places you'll see it, tell yourself 'whatever' when your mind is overcome with unholy thoughts...whatever you need to do to remind yourself to think on these things. Try it for a week and be in prayer and see where God leads you!! He will never fail you!!
Just say WHATEVER!!