Word Origin & History
addle1712, from addle (n.) "urine, liquid filth," from O.E. adela "mud, mire, liquid manure" (cognate with O.Swed. adel "urine," M.L.G. adel, Du. aal "puddle"). Used in noun phrase addle egg (mid-13c.) "egg that does not hatch, rotten egg," lit. "urine egg," a loan-transl. of L. ovum urinum, which is itself
an erroneous loan-transl. of Gk. ourion oon "putrid egg," lit. "wind egg," from ourios "of the wind" (confused by Roman writers with ourios "of urine," from ouron "urine"). Because of this usage, the noun in Eng. was taken as an adj. from c.1600, meaning "putrid," and thence given a fig. extension to "empty, vain, idle," also "confused, muddled, unsound" (1706). The verb followed.