The Collaborative International Dictionary
                    Dubitably
                    
                        
                
                                                                    Dubitable \Du"bi*ta*ble\, a. [L. dubitabilis. Cf.  Doubtable.]
   Liable to be doubted; uncertain. [R.] 
--Dr. H. More. --
    Du"bi*ta*bly, adv. [R.]
Wiktionary
                    dubitably
                    
                        
                
                                                                    a. doubtfully adv. (defn: en)
Usage examples of "dubitably".
But my frustration and anger died in puzzlement when the door was opened to my impatient buzz by none other than friend Mcdougal, older, his face wrinkling, his red hair salted with white, but in dubitably Mac.