Dopey (13)
(Other definitions for gormless that I've seen before include "Dim-witted" , "Lacking initiative/sense" , "Foolish, stupid" , "Lacking the sense one was born with" , "Slow-witted" .)
(Other definitions for unintelligent that I've seen before include "Lacking wit" , "Gormless" , "Foolish" , "Stupid" .)