Senseless maiden in retro hairstyle (4)
I believe the answer is:
numb
'senseless' is the definition.
(thesaurus)
'maiden in retro hairstyle' is the wordplay.
'maiden' becomes 'm' (cricket abbreviation).
'in' means one lot of letters goes inside another.
'retro' shows that the letters should be reversed in order (retro is Latin for 'backwards').
'hairstyle' becomes 'bun'.
'bun' back-to-front is 'nub'.
'm' inserted inside 'nub' is 'NUMB'.
(Other definitions for numb that I've seen before include "Frozen" , "Without sensation" , "Deprived of feeling" , "Insensitive" , "Stunned, insensible" .)