'foreign-looking' is a compound formed in English from 'foreign' and the present participle 'looking'. 'foreign' originates from Old French 'forain' (from Latin 'foraneus'), where Latin 'foris' meant 'outside'; 'look' originates from Old English 'lōcian', meaning 'to look' or 'to direct the eyes'.

'foreign' changed from Latin 'foraneus' → Old French 'forain' → Middle English 'for(e)in' and eventually became modern English 'foreign'; 'look' derives from Old English 'lōcian' and developed into Middle English 'loken'/'loken' and then modern 'look'; the compound 'foreign-looking' was formed in modern English by combining these elements.

Originally 'foreign' carried the sense 'of the outside' (from Latin 'foris') and 'look' meant 'to direct the eyes'; over time the compound came to mean 'appearing to be from another country' or 'having features that suggest a foreign origin'.