It was abnormally restricted in Victorian times (5)
I believe the answer is:
waist
'restricted in victorian times' is the definition.
Although both the answer and definition are singular nouns, I don't understand how one could define the other.
'it was abnormally' is the wordplay.
'abnormally' is an anagram indicator.
'it'+'was'='itwas'
'itwas' with letters rearranged gives 'WAIST'.
Can you help me to learn more?
(Other definitions for waist that I've seen before include "Midriff" , "Narrow part of body" , "Ship's middle" , "Spare tyre location?" , "part of frame" .)