Blunderingly

adv. [f. prec. + -LY².] In a blundering manner.

1807.  G. Chalmers, Caledonia, I. II. iii. 248. This king … is mentioned, blunderingly, by Langhorn.

1838–9.  Hallam, Hist. Lit., I. I. ii. § 30. A calendar … blunderingly ascribed to Roger Bacon.

1879.  G. Meredith, Egoist, II. iii. 46. She perceived how blunderingly she had acted.