Chewing over is an idiom that means to think carefully about or ponder something. Antonyms for this phrase would include words that imply a lack of deep thought or consideration. For example, the word "superficially" suggests a surface-level examination rather than a deep analysis. Alternatively, "disregard" would imply a complete lack of consideration or attention. "Ignore" would similarly suggest a lack of attention or thoughtfulness. Antonyms for "chewing over" would therefore be words that imply a lack of thought or consideration, or a failure to engage with an idea in a meaningful way.