The Collaborative International Dictionary of English v.0.48:

Ettle \Et"tle\, v. t. [Perh. the same word as addle to earn; bur
   cf. OE. atlien, etlien, to intend, prepare, Icel. [ae]tla to
   think, suppose, mean.]
   To earn. [Obs.] See Addle, to earn. --Boucher.
   [1913 Webster]