impeccable

The adjective impeccable describes something or someone without any flaws. A stand-up comedian needs impeccable timing for her jokes to work.

The adjective impeccable refers to something or someone without marking or error — but it can describe something spotless or clean. The word comes from the Latin impeccabilis, "to be sinless," which is also an outdated sense in English. You can see how "clean" comes from "sinless." Because of the messy nature of picnic food, it is highly unlikely that you would leave with your clothing still as impeccable as when you arrived, especially if you like lots of mustard and ketchup!