Very many without an anaesthetic (10)
I believe the answer is:
numberless
This clue could be a double definition.
'very many' is the first definition.
'numberless' can be an answer for 'many' (thesaurus). I'm not sure about the 'very' bit.
'without an anaesthetic' is the second definition.
('anaesthetic' can be 'number' (i.e. something that makes things numb) so maybe 'without an anaesthetic' can be ''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" .)