The antonyms for the phrase "let sunlight in" could include "shut out the light," "keep the shades drawn," or "close the shutters." These phrases all suggest a deliberate and intentional effort to block out natural light, either for practical purposes like reducing glare or for personal preferences like a desire for privacy. Conversely, the phrase "let sunlight in" conveys a sense of openness, warmth, and optimism. It suggests a willingness to embrace the outside world and to be receptive to new experiences. Overall, choosing whether to let sunlight in or shut it out can have a significant impact on one's mood, productivity, and overall wellbeing.