The anaesthetic has a figure (6)
I believe the answer is:
number
I believe this is a double definition.
'the anaesthetic' is the first definition.
(i.e. something that makes things numb)
'a figure' is the second definition.
(I've seen this before)
'has' acts as a link.
(Other definitions for number that I've seen before include "No longer" , "1,2,3, for instance" , "comparatively lacking in feeling" , "For example, one" , "Quantity, amount; song" .)