Conventional mother at home with awkward master (10)
I believe the answer is:
mainstream
'conventional' is the definition.
(I've seen this before)
'mother at home with awkward master' is the wordplay.
'mother' becomes 'ma' (Ma is another word for mother or mum).
'at home' becomes 'in' ('I'm in' can mean 'I'm at home').
'with' means one lot of letters go next to another.
'awkward' is an anagram indicator.
'master' with letters rearranged gives 'stream'.
'ma'+'in'+'stream'='MAINSTREAM'
(Other definitions for mainstream that I've seen before include "Current" , "entirely conventional?" , "Relating to what is normal or standard" , "Conventional, normal" , "In accordance with what is normal or standard" .)