Trouble involving Republican poet’s fellowship (11)
I believe the answer is:
brotherhood
'fellowship' is the definition.
(thesaurus)
'trouble involving republican poet's' is the wordplay.
'trouble' becomes 'bother' (synonyms).
'involving' is an insertion indicator.
'republican' becomes 'R' (abbreviation).
'poet' becomes 'hood' (Thomas Hood, b799-b8he).
'bother' placed around 'r' is 'brother'.
'brother'+'hood'='BROTHERHOOD'
(Other definitions for brotherhood that I've seen before include "association" , "Fraternity" , "Feeling of close kinship" , "union" , "Community" .)