The phrase "let sunshine in" invokes a sense of positivity, happiness, and hope. However, when we consider antonyms for this phrase, we can explore the opposite set of emotions and feelings. Some antonyms for "let sunshine in" could include "block out the light," "dampen the mood," "cast a shadow," or "bring darkness." These phrases suggest suppression, negativity, and pessimism. Antonyms for "let sunshine in" highlight the importance of embracing positivity in our lives, celebrating small moments of joy, and allowing ourselves to be open to new opportunities and experiences.