Baltic citizen and public school pupil carrying son (8)
I believe the answer is:
estonian
'baltic citizen' is the definition.
(Estonia is a Baltic nation)
'public school pupil carrying son' is the wordplay.
'public school pupil' becomes 'etonian' (I've seen this before).
'carrying' means one lot of letters goes inside another.
'son' becomes 's' (genealogical abbreviation for son).
'etonian' placed around 's' is 'ESTONIAN'.
'and' is the link.
(Other definitions for estonian that I've seen before include "European language" , "Eastern European" , "Native of a Baltic republic" , "Foreign" , "Northern European" .)