Foreign language (6)
'foreign language' is the definition.
(I've seen this before)
This is all the clue.
(Other definitions for arabic that I've seen before include "foreign language" , "There's a CIA bar on this language, oddly" , "Major language of Middle East" , "Middle Eastern language" , "Language widespread in Middle East and N Africa" .)
(Other definitions for portuguese that I've seen before include "Language of Brazil" , "description of a man-of-war?" , "EU national" , "Like da Gama" , "Eg, Native to Lisbon" .)