Antonyms for the phrase "be prevalent" can be "be rare," "be uncommon," "be infrequent," "be scarce," "be unusual," or "be atypical." These antonyms suggest that the occurrence or existence of something is not widespread or usual in a particular context. For instance, a disease that is prevalent in a community may have antonyms such as a disease that is rare or infrequent. Similarly, social practices or behaviors that are prevalent may have antonyms such as those that are atypical or unusual. Understanding the antonyms for "be prevalent" can help individuals identify when something is not widely accepted or practiced, and better navigate social and cultural contexts.