A Welsh girl or one from Japan, say? (5)
I believe the answer is:
asian
'one from japan say?' is the definition.
(I've seen this in another clue)
'a welsh girl' is the wordplay.
'welsh girl' becomes 'sian' (common Welsh name).
'a'+'sian'='ASIAN'
'or' acts as a link.
(Other definitions for asian that I've seen before include "On vast continent" , "like the majority of people" , "Continental native" , "eg Pakistani" , "Relating to one continent" .)