pur sang
/ˌpʊə ˈsɒŋ/ /ˌpʊə ˈsɑːŋ/(also pure sang)
adjective
Of unmixed origin or descent, pure-blooded; genuine; unadulterated.
noun
Unmixed origin or descent, pure blood; a pure-blooded or genuine person or thing.
adverb
In all respects, through and through; genuinely, strictly; without adulteration.
Origin
Mid 19th century; earliest use found in The Times. From French pur sang (noun) unmixed origin or descent, pure-blooded or genuine person, thoroughbred horse, (adjective) pure-blooded from pur + sang blood.