Even the team is upset with a co-resident (8)
I believe the answer is:
flatmate
'a co-resident' is the definition.
I can't judge whether this definition defines the answer.
'even the team is upset' is the wordplay.
'even' becomes 'flat' (similar in meaning).
'is upset' is an anagram indicator (I've seen 'are upset' mean this).
'team' with letters rearranged gives 'mate'.
'flat'+'mate'='FLATMATE'
'with' acts as a link.
Can you help me to learn more?
(Other definitions for flatmate that I've seen before include "Cohabitee" , "Fellow apartment resident" , "in the rooms one shares" , "fellow lodger" , "Person sharing accommodation" .)