The term "non observant" typically refers to someone who does not follow religious customs, but there are plenty of antonyms for this term. If someone is "observant," they would be following religious traditions and customs. However, there are also other words that could be used to describe someone who is not "non observant." For example, "pious" would be an antonym for someone who is not devout, "religious" for someone who is not spiritual, and "faithful" for someone who is not committed to their beliefs. Other potential antonyms could include "devout," "traditional," or "obedient" depending on the context.