Not so many we infer (5)
I believe the answer is:
fewer
'not so many' is the definition.
('few' can be the opposite of 'many' so perhaps 'fewer' is reasonable for 'not so many')
'we infer' is the wordplay.
I cannot quite understand how this works, but
'we' is present in the answer.
The remaining letters 'fer' is a valid word which might be clued in a way I don't understand.
This explanation may well be incorrect...
Can you help me to learn more?
(Other definitions for fewer that I've seen before include "smaller number of people" , "Reduced" , "Less in number" , "in smaller numbers" , "Not so many" .)