Cause of cracks that can bring down the house (5)
I believe the answer is:
comic
'cause' is the definition.
(I know that comic is a type of actor)
'cracks that can bring down the house' is the wordplay.
I cannot really understand how this works, but
'the house' could be 'co' (I've seen this in other clues) and 'co' is found in the answer.
The remaining letters 'mic' is a valid word which might be clued in a way I don't see.
This explanation may well be incorrect...
'of' acts as a link.
Can you help me to learn more?
(Other definitions for comic that I've seen before include "Causing laughter" , "Stand-up possibly" , "Priceless" , "Funny (person, paper)" , "Funny; comedian" .)