Not exactly hideous place of concealment (7)
I believe the answer is:
hideout
This clue could be a double definition.
'not exactly hideous place' is the first definition.
'hideout' can be an answer for 'place' (hideout is a kind of place). I am not sure about the 'not exactly hideous' bit.
'concealment' is the second definition.
(thesaurus)
'of' acts as a link.
Can you help me to learn more?
(Other definitions for hideout that I've seen before include "den" , "retreat" , "sanctuary" , "Place to lie low" .)