Cause suffering to (3)
(Other definitions for ail that I've seen before include "Be ill or unwell" , "Worry" , "Be the worse for wear" , "Afflict -- feel unwell" , "distress" .)
'cause suffering to' is the definition.
(I've seen this before)
This is the entire clue.
(Other definitions for afflict that I've seen before include "Vex" , "Cause to suffer" , "Cause suffering to" , "Distress mentally or physically" , "Painfully affect" .)