dreadly

from The Collaborative International Dictionary of English v.0.48

Dreadly \Dread"ly\, a.
   Dreadful. [Obs.] "Dreadly spectacle." --Spenser. -- adv. With
   dread. [Obs.] "Dreadly to shake." --Sylvester (Du Bartas).
   [1913 Webster]