Gold standard protects one foreign worker (2,4)
I believe the answer is:
au pair
'foreign worker' is the definition.
The definition and answer can be both people as well as being singular nouns.
Maybe they are linked in a way I don't understand?
'gold standard protects one' is the wordplay.
'gold' becomes 'Au' (Au is the chemical symbol for gold).
'standard' becomes 'par' (standard of play in golf).
'protects' is an insertion indicator (outer letters protect inside letters).
'one' becomes 'i' (Roman numeral).
'par' placed around 'i' is 'pair'.
'au'+'pair'='AU PAIR'
Can you help me to learn more?
(Other definitions for au pair that I've seen before include "Foreign home helper" , "Foreign girl who does housework for her keep" , "Family assistant" , "Live-in young foreigner expected to do household chores" , "Foreign girl who provides domestic help for food and board" .)