A second-class way to get overseas (6)
I believe the answer is:
abroad
'overseas' is the definition.
(synonyms)
'a second-class way' is the wordplay.
'second class' becomes 'b'.
'way' becomes 'road' (road is a kind of way).
'a'+'b'+'road'='ABROAD'
'to get' acts as a link.
(Other definitions for abroad that I've seen before include "to France, maybe" , "At large; widely current" , "Stare lecherously at (someone)" , "Away in another country" , "In foreign land" .)