The phrase "is habit of" can be replaced with a number of synonyms depending on the context. Some examples include "tendency," "inclination," "propensity," "regular practice," "custom," "tradition," "routine," "second nature," and "usual behavior." Each of these synonyms emphasizes a different aspect of the concept of habit, from an ingrained pattern of behavior to a cultural norm. By using these interchangeable terms, writers can add variety and precision to their language, and help readers better understand the specific nuances of the habits they are discussing.