Country again bitter about quarantining rules, primarily (5,7)
I believe the answer is:
great britain
'country' is the definition.
(Great Britain is an example)
'again bitter about quarantining rules primarily' is the wordplay.
'about' is an anagram indicator.
'quarantining' is an insertion indicator (quarantine can mean to contain).
'primarily' suggests taking the first letters.
The first letter of 'rules' is 'r'.
'again'+'bitter'='againbitter'
'againbitter' with letters rearranged gives 'greatbitain'.
'greatbitain' placed around 'r' is 'GREAT BRITAIN'.
(Other definitions for great britain that I've seen before include "GB in full" , "Part of the UK" , "Europe's biggest island" , "North European country" , "island for us" .)