Suffer in an old-fashioned way (3)
I believe the answer is:
let
'suffer' is the definition.
(I've seen this in another clue)
'in an old-fashioned way' is the wordplay.
'in' is an insertion indicator.
'an old fashioned' becomes 'lt' (I am not sure about this - if you are sure you should give a lot more credence to this answer).
'way' becomes 'e' (Compass direction - East).
'lt' placed around 'e' is 'LET'.
Can you help me to learn more?
(Other definitions for let that I've seen before include "Disappoint or fail to support - ... down" , "Allow or rent" , "Rent out: grant" , "Allow; leased" , "Service that must be repeated" .)