Dread detention (12)
I believe the answer is:
apprehension
I believe this is a double definition.
'dread' is the first definition.
(I've seen this before)
'detention' is the second definition.
(thesaurus)
(Other definitions for apprehension that I've seen before include "Trepidation" , "Fearful anticipation" , "Anxious anticipation; understanding" , "Arrest -- dread" , "Fear" .)