The phrase "chafing inwardly" indicates an internal irritation or frustration that one experiences but does not express outwardly. Antonyms for this phrase would be words that signify a lack of internal turmoil or agitation. Some antonyms could be "calmly accepting," "peaceful," "tranquil," "composed," or "serene." These words suggest a sense of inner calm and acceptance, rather than the restless and irritated feeling associated with "chafing inwardly." Using antonyms such as these can help provide a more nuanced understanding of a situation or character in writing, allowing for a greater range of emotion and expression.