Ill, say, like this (3)
I believe the answer is:
sic
'this' is the definition.
Both the definition and answer are adverbs.
Perhaps there's a link between them I don't understand?
'ill say' is the wordplay.
'ill' becomes 'sick' (synonyms).
'say' indicates a 'sounds like' (homophone) clue.
'sick' sounds like 'SIC'.
'like' acts as a link.
Can you help me to learn more?
(Other definitions for sic that I've seen before include "Thus - in Latin" , "Thus among musicians" , "Word to call attention to a quoted mistake" , "(Of quoted word) exactly so" , "Urge to attack" .)