The word "catches on to" refers to understanding, comprehension or grasping the meaning of something. The antonyms for this phrase include confusion, misunderstanding, incomprehension or unawareness. Therefore, if someone doesn't "catch on to" an idea or concept, they could be considered uninformed or clueless. This can be due to various reasons such as language barriers, lack of background knowledge or cognitive challenges. To avoid these challenges, it is important to strive for clear communication, use simpler language and provide enough context for people to understand. Ultimately, improving communication and understanding among individuals can create a more cohesive society.