Fate of idiot atop house (6)
I believe the answer is:
clotho
'fate' is the definition.
(one of the Fates of Greek mythology)
'idiot atop house' is the wordplay.
I cannot really see how this works, but
'idiot' could be 'clot' (I've seen this before) and 'clot' is found within the answer.
'house' could be 'ho' (abbreviation for house) and 'ho' is found in the answer.
No letters remain.
This may be the basis of the clue (or it may be nonsense).
'of' acts as a link.
Can you help me to learn more?
(Other definitions for clotho that I've seen before include "Fate who spun thread of life" , "puff-adder" , "One of the three Fates in Greek mythology" , "One of the three Fates (she spins!)" , "female controlling destiny" .)