Like a peer around mostly boring houses (5)
I believe the answer is:
ducal
'like a peer around mostly boring houses' is the definition.
I can't judge whether this definition defines the answer.
'like a peer around mostly boring' is the wordplay.
'like a peer' becomes 'dual' (I am not sure about this - if you are sure you should give a lot more credence to this answer).
'around' becomes 'ca' (circa).
'mostly' means to remove the last letter (most but not all of the word).
'boring' indicates putting letters inside (to bore something can mean to drill into it).
'ca' with its last letter taken off is 'c'.
'dual' enclosing 'c' is 'DUCAL'.
Can you help me to learn more?
(Other definitions for ducal that I've seen before include "Aristocratic" , "Relating to a noble" , "Representing noble" , "Pertaining to a duke" , "Relating to the highest British hereditary title" .)