Meaning of subnormalPronunciation: (sub-nôr'mul), [key]- below the normal; less than or inferior to the normal: a subnormal amount of rain. - being less than average in any psychological trait, as intelligence, personality, or emotional adjustment. - a subnormal person.- that part of the x-axis of a curve cut off between the ordinate and a normal.- subnormal (Thesaurus)