One with obsession to cool attic, but only one time (7)
I believe the answer is:
fanatic
This clue might be a double definition.
'one with obsession' is the first definition.
(someone fanatical about something)
'cool attic but only one time' is the second definition.
Both the answer and definition are adjectives. Perhaps you can see a link between them that I can't see?
'to' acts as a link.
(Other definitions for fanatic that I've seen before include "Person filled with excessive zeal for cause" , "One who is excessively zealous" , "Zealot or extremist" , "Overzealous person" , "Over-enthusiastic person" .)