There are many antonyms for the phrase "let next to," which typically denotes a sense of approval, agreement, or acceptance. Some possible antonyms include "disapprove of," "oppose," "reject," "condemn," "disagree with," or "criticize." Each of these words implies a sense of disapproval or disagreement with the thing that is "next to" or being considered. By using one of these antonyms instead of "let next to," a speaker or writer can convey a more negative or critical tone towards the subject at hand. Consider the context and audience carefully when selecting an antonym, as certain choices may be more appropriate or effective in different situations.