addle

From Middle English adel (“rotten”), from Old English adel, adela (“mire, pool, liquid excrement”), from Proto-West Germanic adal, from Proto-Germanic adalaz, *adalô (“cattle urine, liquid manure”). Akin to Scots adill, North Frisian ethel (“urine”), Saterland Frisian adel (“dung”), Middle Low German adele (“mud, liquid manure”) (Dutch aal (“liquid manure”)), Old Swedish adel (“urine”), Danish ajle (“liquid manure”), Bavarian Adel (“liquid manure”).

Inherited from Middle English addlen, adlen, probably from Old Norse ǫðlask (“to gain possession of property”), from ōðal (“owndom, property”).