The phrase "wising off" is informal slang and might not be present in everyone's vernacular. Some synonyms for this expression might be "talking back", "disrespecting", "sassing", "being cheeky", "answering back", or "giving lip". These phrases imply that the person is being rude, argumentative or insolent in their behavior or reply. However, it's worth noting that the context and tone of the conversation might alter the meaning of these expressions, so it's essential to consider the situation before using them. In any case, it's always advisable to maintain a level of respect and politeness with others.