Sentence:  ( 1 ) When an object was placed in the patient 's hand , he had no difficulty determining whether it was warm or cold , sharp or blunt , rough or <WSD>smooth</WSD> , flexible , soft , or hard ; and he could tell , simply by the feel of it , whether it was made of wood , iron , cloth , rubber , and so on . 
Meaning of the word marked with <WSD> tags:  having a surface free from roughness or bumps or ridges or irregularities