Lol I think that’s a different spelling. It’s short for lunatic....so, lune?
looney
loon·y or loon·ey also lun·y (lo͞o′nē)Informal
adj. loon·i·er, loon·i·est also lun·i·er or lun·i·est
1. Extremely foolish or silly.
2. Mentally deranged; crazy.
n. pl. loon·ies or loon·eys also lun·ies
A foolish or crazy person.
Shortening and alteration of lunatic, or from loon.]
loon 2 (lo͞on)
n. Informal
A person who is foolish or crazy.