Feel regret after tea? That's correct (4)
I believe the answer is:
true
'correct' is the definition.
(associated in meaning)
'feel regret after tea?' is the wordplay.
'feel regret' becomes 'rue' (I've seen this before).
'after' means one lot of letters go next to another.
'tea?' becomes 't' (I've seen this in other clues).
'rue' put after 't' is 'TRUE'.
'that's' is the link.
(Other definitions for true that I've seen before include "indeed" , "In accordance with fact" , "Factually accurate" , "In accordance with facts" , "Corrected" .)