The term "hard-line" is often used to describe someone who is strict or uncompromising in their viewpoints or actions. There are several synonyms for this term which can be used to add variety and nuance to your writing. Some alternatives to "hard-line" include inflexible, steadfast, unbending, unyielding, unrelenting, and uncompromising. These words all express a similar idea, but each has its own particular connotations. For example, "unbending" or "unyielding" might suggest a certain rigidity or stubbornness, whereas "unrelenting" may convey a sense of relentlessness or determination. Choosing the right synonym can help to add depth and clarity to your writing and make it more engaging for your reader.