When we chew over something, we contemplate and ponder over it deeply. Synonyms for the phrase "chewed over" include "deliberate", "consider", "mull over", "reflect", "muse", "ruminate", "meditate", "speculate", "contemplate", "ponder", "revolve", "weigh", "scrutinize", "analyze", "evaluate", "think about" and "assess". All of these words imply a thoughtful or thorough consideration of a subject or problem. It's important to have a range of synonyms when writing or speaking, as it allows us to convey our ideas in a more precise and nuanced manner.