The antonyms for the phrase "shutting in" are broad and varied. When you say "shutting in," you probably think of confining, limiting, or restricting something. The opposite of this would be more along the lines of setting free, releasing, liberating, or expanding. Additionally, antonyms for "shutting in" would include phrases like "opening up" or "making more accessible," as well as relinquishing control, eliminating barriers, or demolishing obstacle. In essence, while the action of "shutting in" denotes a sort of confinement, the antonyms connote the idea of breaking free and embracing the things that lie beyond boundaries.