loonnoun
1- Any of several fish-eating diving birds of the genus Gavia of northern regions, having a short tail, webbed feet, and a laughlike cry.
2- One who is crazy or deranged.
3- A stupid fellow; a clown: with various shades of intensity as an opprobrious epithet, like fool, dolt, etc.
lunaticnoun
1- A person who is affected by lunacy; a mentally deranged person.
2- A very foolish person.
3- A person affected with lunacy; specifically, an insane person who has lucid intervals, or one whose unsoundness of mind is acquired, not congenital, as distinguished from an idiot.