This chap is a Pacific country’s star (8)
I believe the answer is:
hesperus
'star' is the definition.
(I've seen this before)
'this chap is a pacific country's' is the wordplay.
I cannot quite see how this works, but
'chap' could be 'he' and 'he' is located in the answer.
'a' could be 'per' (eg 'one a day' means 'one per day') and 'per' is found in the answer.
'country's' could be 'us' (US is an example) and 'us' is present in the answer.
A single letter 's' remains which might be clued in a way I don't see.
This may be the basis of the clue (or it may be nonsense).
Can you help me to learn more?
(Other definitions for hesperus that I've seen before include "star in the evenings" , "Evening star; Longfellow's Wreck" , "Name for Venus" , "Longfellow poem 'The Wreck of the ??..' (8)" .)