Shouts and upsets the hosts (9)
I believe the answer is:
thousands
'hosts' is the definition.
Although both the answer and definition are plural nouns, I can't see how one could define the other.
'shouts and upsets' is the wordplay.
'upsets' is an anagram indicator.
'shouts'+'and'='shoutsand'
'shoutsand' with letters rearranged gives 'THOUSANDS'.
'the' acts as a link.
Can you help me to learn more?
(Other definitions for thousands that I've seen before include "Crowds" , "large sum?" , "Large numbers" , "a lot" , "1000s" .)