Criminal set-up and taken by surprise (10)
I believe the answer is:
confounded
'taken by surprise' is the definition.
The answer and definition can be both related to thinking as well as being past participle verbs.
Maybe you can see an association between them that I can't see?
'criminal set-up' is the wordplay.
'criminal' becomes 'con' (abbreviation for 'convict').
'set up' becomes 'founded' (I've seen this in other clues).
'con'+'founded'='CONFOUNDED'
'and' is the link.
Can you help me to learn more?
(Other definitions for confounded that I've seen before include "Surprised" , "Really annoying (nuisance)" , "Perplexed - damned" , "ending of Te Deum?" , "Confused; astonished" .)