It comes from old-school boxing. "Inclined to fight" was the original meaning. Bellicose is closer than belligerent. Certainly undignified, traditionally at

It comes from old-school boxing. "Inclined to fight" was the original meaning. Bellicose is closer than belligerent. Certainly undignified, traditionally at least. In the last few decades it has been used for underdogs, as in "he's small but scrappy-" giving it that positive implication you mention- small but always ready to fight. Think scrappy-doo