They suffer writing penned by smartypants? (7)
I believe the answer is:
martyrs
'they suffer' is the definition.
(a martyr is made to suffer)
'writing penned by smartypants?' is the wordplay.
I cannot really see how this works, but
'writing' could be 'r' (one of the traditional three R's of education) and 'r' is present in the answer.
'by' could be 'at' and 'at' is present in the remaining letters.
This explanation may well be incorrect...
Can you help me to learn more?
(Other definitions for martyrs that I've seen before include "Persons suffering for their beliefs" , "People who die for their cause" , "They suffer for their principles" , "They suffer for a principle" , "people who suffer" .)