The word "darnedest" is an adjective used to describe something as the extreme or utmost of its kind. It can also be used to indicate that something is surprising or unexpected. However, there are several synonyms for this word. The word "strangest" could be used to describe something that is particularly odd or out of the ordinary. "Weirdest" could be applied to something that is particularly unsettling or uncanny. "Most exceptional" could be used to describe something that is particularly outstanding or of great quality. "Most unusual" could also be used to describe something that is particularly rare or uncommon.