Regret entering Turkey? That's more accurate (5)
I believe the answer is:
truer
'more accurate' is the definition.
('true' can be similar in meaning to 'accurate')
'regret entering turkey?' is the wordplay.
'regret' becomes 'rue' (to rue something is to regret it).
'entering' means one lot of letters goes inside another.
'turkey?' becomes 'tr' (abbreviation eg in internet addresses).
'rue' placed inside 'tr' is 'TRUER'.
'that's' acts as a link.
(Other definitions for truer that I've seen before include "More faithful or straight" , "More exact" , "More relaible" , "More straight and veracious" , "More in accordance with fact" .)