Way big house is spoken of (6)
I believe the answer is:
manner
'way' is the definition.
(synonyms)
'big house is spoken of' is the wordplay.
'big house' becomes 'manor' (large home).
'is spoken of' indicates a 'sounds like' (homophone) clue.
'manor' sounds like 'MANNER'.
(Other definitions for manner that I've seen before include "Way of acting or behaving" , "Style, way" , "Way of doing something, or general attitude" , "Mode" , "Fashion, way" .)