Such a nice sounding word. If you say addlepated with just the right tone with a smile on your face, it sounds like a compliment. “You are such an addlepated individual.” If you leave them confused, then they really are an addlepated individual.

Related words such as addlebrained or addle-headed sound much more like the insult they are. The word pate comes from Middle English and refers to the crown of the head, the head with the brain, or even the brain itself.

Addle is the more fun word, commonly meaning to confuse. So, an addled person is a confused person.

The best linguistic guesses to the evolution is a series of misinterpretations. In Ancient Greece, ourios referred to wind. Ourion ōon translated then literally to “wind egg.” Thus, you can see how a rotten egg when cracked open would produce a terrible smell in the air. But ouron meant urine.

The two similar words became intwined in Latin as ovum urinum, or urine egg. Now there is an appetizing thought.

By the time the phrase worked its way through the centuries and various European languages, the Middle English phrase was “addle egg,” or a rotten egg. In a broader sense, addle meant putrid, but also urine, dung, manure, and various other putrid smells.

Thus, you can see the clarity in referring to someone as dung brains (which still exists in modern English in a more crass phrase). Addle-brained, or addlepated, is just the more polite phrase, though with the same meaning.