The term "old softie" is often used to describe someone who is overly sentimental or emotional. However, there are many antonyms for this term that describe different personalities entirely. Some opposite words could be "hard-nosed," "tough-minded," or "unyielding," which suggest someone who is stoic and resolute in their beliefs. Other antonyms might include "detached," "calculated," or "aloof," which describe someone who is cool and dispassionate. Still, others might include "brutal," "cruel," or "merciless," which signify someone who is harsh and unforgiving. In any case, there are many ways to describe the opposite of an "old softie.