Platt's dictionary defines
nāz (
ناز) as "blandishment, coquetry, playfulness, amorous playfulness, feigned disdain; dalliance, toying; fondling, coaxing, soothing or endearing expression; — pride, conceit, consequential airs, whims; — softness, delicacy; elegance, gracefulness". So a range of meaning not found in any particular English word (thus fulfilling the definition of "untranslatable") but pretty far from the definition "pride and assurance that comes from knowing you are loved unconditionally".
"Richmond is a real scholar; Owen just learns languages because he can't bear not to know what other people are saying."--Margaret Lattimore on her two sons