Although many believe that the word loony came from the loon’s laugh-like call, the word loony, or looney, is just a short version of the word lunatic.
Lunatic has been in use for almost 1,000 years and comes from luna, the “moon,” based on the belief that insanity was affected by the moon’s phases.
In contrast, the bird was first called a loon little more than 300 years ago.
The name probably comes from people confusing it with another diving water bird called a loom.
The two had a couple of things in common and the name stuck, having nothing to do with the bird’s call or any other specific characteristic.