The phrase "strong-arm" refers to the act of using force or intimidation to get what one wants, usually in a coercive or aggressive manner. There are several related words, which can be used as synonyms for "strong-arm," including coerce, bully, pressure, intimidate, and domineer. Other synonyms include manipulate, pressurize, browbeat, extract, and compel. In general, these words imply that the person is seeking to exert control over others or a situation, often in an unfair or unethical manner. Using these words will allow you to convey the same meaning as "strong-arm" without being repetitive in your writing.