Very many without an anaesthetic (10)
I believe the answer is:
numberless
'very many without an anaesthetic' is the definition.
I can't judge whether this definition defines the answer.
'very many without' is the wordplay.
'very many' becomes 'number' (I am not sure about this - if you are sure you should believe this answer much more).
'without' becomes 'less'.
'number'+'less'='NUMBERLESS'
Can you help me to learn more?
(Other definitions for numberless that I've seen before include "Too many to count" , "they cannot be counted" .)