The term "most itsybitsy" is used to describe something that is incredibly small or tiny. Antonyms for this word include "immense," "huge," "gigantic," and "enormous." These words all imply a large size, which is the opposite of itsybitsy. Other antonyms for "most itsybitsy" include "big," "large," "massive," and "substantial." These words all convey the idea of something that is substantial or considerable in size. While "most itsybitsy" is often used to describe something cute or charming, the antonyms for this word suggest power, strength, and size.