MEANING: adjective:
1. In a dreamy state.
2. Romantically dazed.
3. Mentally deranged.

ETYMOLOGY: From the belief that a person behaving erratically was under the influence of the moon. From moon + struck, past participle of strike, from Old English strican. Earliest documented use: 1674.

NOTES: The moon never made anyone loony, but it’s a popular excuse for erratic behavior. No one is turning into a werewolf, whether it’s a full-moon or new moon. See this article Lunacy and the Full Moon from the Scientific American.

MORON'S TRUCK - You mean that idiot has a tractor-trailer rig?

MUON STRUCK - hit by a subatomic particle

MOON STRUNK - make a derisive gesture at the co-author of a prominent Style Handbook