Hitting upon is a phrasal verb that means to discover or come up with an idea. The opposite of hitting upon would be failing to discover or not being able to think of an idea. Some antonyms for hitting upon include ignoring, neglecting, missing, overlooking, and disregarding. While hitting upon is about stumbling upon something, antonyms for this phrasal verb are about missing something. Hitting upon usually involves an unexpected encounter or discovery, while its antonyms involve a lack of attention or focus. When looking for an antonym for hitting upon, think about words that suggest not finding something or not paying attention to it.