Most intolerant home in which there is a right bust-up (9)
I believe the answer is:
narrowest
'most intolerant' is the definition.
Both the definition and answer are superlative adjectives. Perhaps there's a link between them I don't understand?
'home in which there is a right bust-up' is the wordplay.
'home' becomes 'nest' (a bird's home).
'in which' means one lot of letters goes inside another.
'there is a right bust up' becomes 'arrow' (I can't justify this - if you can you should give a lot more credence to this answer).
'nest' placed around 'arrow' is 'NARROWEST'.
Can you help me to learn more?
(Other definitions for narrowest that I've seen before include "Slightest" , "Most confined" , "Most slender" , "Being most thin" , "Extremely strict" .)