20 across
Andorra
terribly
treated
in
an
experimental
way?
(2,5,3,5)
Andorra terribly treated in an experimental way? (2,5,3,5)
hints
0
checks
0
hints
The definition is at the end of the clue.
How the clue works
Look at in an experimental way? — that's your definition. Then take "Andorra terribly" and notice that "treated" is flagging an anagram, so you jumble all those letters about to get BY TRIAL AND ERROR.