Consider it abnormal showing reserve (10)
I believe the answer is:
discretion
'reserve' is the definition.
(thesaurus)
'consider it abnormal' is the wordplay.
'abnormal' indicates anagramming the letters.
'consider'+'it'='considerit'
'considerit' with letters rearranged gives 'DISCRETION'.
'showing' is the link.
(Other definitions for discretion that I've seen before include "Tactful quality" , "Diplomacy" , "Freedom to decide on an action" , "Tact - prudence" , "The better part of valour" .)