We can thank the intrepid sailors of yore for these wildly descriptive terms.

Many tried to carry out the deed of the intrepid mountaineer.

Intrepidly, he jumped out of the plane.

You've got to be intrepid!

Our seamen have always been famous for a matchless alacrity and intrepidity in time of danger; this has saved many a British ship, when other seamen would have run below deck, and left the ship to the mercy of the waves, or, perhaps, of a more cruel enemy, a pirate.