Definition
Something done 'substantially' is done to a large extent or in a significant way. It implies more than just a little, but perhaps not completely. Think of it as a heavy ingredient in a recipe—noticeable and impactful. It's like adding a 'substantial' amount of chocolate chips to your cookies. Not all chocolate, but definitely enough to make a difference. In contrast to 'slightly' or 'partially', it indicates a considerable change.