The phrase "most cattish" can be replaced with a number of synonyms that capture the essence of this expression. Some alternative phrases that could be used include "most feline," "most sly," "most sneaky," "most cunning," or "most devious." Each of these phrases evokes a different aspect of the stereotypical "cat-like" personality, which is often associated with qualities such as cleverness, playfulness, and a certain aloofness. Depending on the context in which it is used, any of these synonyms could be an appropriate substitute for the phrase "most cattish".