The verb "daunt" means to make someone feel intimidated. To "daunt" your opponent means to lessen his courage. The word "daunting" is an adjective. You use it to describe a noun. For example "task". A task is a piece of work to be done. If I say "a daunting task" I am describing a piece of work that intimidates me.
"I need to finish my French homework by Friday but it's a daunting task."
So the word "daunting" really has this feeling of intimidation. You use it to describe things that can overwhelm you and make you quit.
However, if I say "he was a dauntless hero", it means he was a hero that cannot be intimidated.