"Not in keeping" is a phrase that denotes something that is not compatible with a particular norm or standard. There are many synonyms that can be used to describe this term, such as inappropriate, incongruous, unsuitable, unfitting, improper, out of place, discordant, divergent, incompatible, deviant, and aberrant. Each of these words carries a unique connotation that can be used to convey different shades of meaning when describing something that is not in keeping with a particular context. By using these synonyms effectively, writers can add depth and nuance to their writing and create a more impactful message.