The antonyms for non-strict are varied, and depend on the context in which the term is used. In the case of non-strict rules, regulations or guidelines, the antonyms could be rigorous, stringent, or even authoritarian. For non-strict diets or exercise routines, antonyms could be intense, rigorous or demanding. When non-strict is used in relation to a person's behavior, antonyms could include cautious, careful, attentive, or measured. Regarding laws or policies, antonyms could include uncompromising, rigorous, or inflexible. The word non-strict is highly context-sensitive and has a broad range of antonyms, depending on the subject matter.