Average – unpleasant (4)
I believe the answer is:
mean
I believe this is a double definition.
'average' is the first definition.
(type of average)
'unpleasant' is the second definition.
(thesaurus)
(Other definitions for mean that I've seen before include "Tight - average" , "Intend; not generous" , "Average; inferior; intend" , "Aim - low - average" , "'Midway, average (4)'" .)