The phrase "soft on" generally refers to someone being lenient or lacking a firm stance on a particular issue. There are several synonyms that can be used to convey the same meaning, such as "lenient towards," "permissive," "tolerant of," "indulgent," or "forgiving of." These words describe a person who is not strict or firm in their approach and may allow others to get away with certain things. In another context, "soft on" may also refer to being sympathetic to or supportive of a particular group or cause. In this case, synonyms could include "favorable towards," "supportive of," or "advocate for".