Aberrant (3)
'aberrant' is the definition.
(thesaurus)
This is the entire clue.
(Other definitions for odd that I've seen before include "Not even; strange" , "Unusual, strange" , "Strange, bizarre" , "Peculiar or unpaired" , "like half the numbers?" .)
'aberrant' is the definition.
(similar in meaning)
This is all the clue.
(Other definitions for abnormal that I've seen before include "Extraordinary" , "'Aberrant, atypical (8)'" , "Not typical or usual" , "Different to what is ordinary or expected" , "Deviant, different from the usual" .)