Show off national treasure’s privates (5,6)
I believe the answer is:
crown jewels
'privates' is the definition.
Although both the answer and definition are singular nouns, I don't understand how one could define the other.
'show off national treasure's' is the wordplay.
'show off' becomes 'crow'.
'national' becomes 'n' (abbreviation listed in Chambers).
'treasure's' becomes 'jewel's' (jewel is a kind of treasure).
'crow'+'n'+'jewels'='CROWN JEWELS'
Can you help me to learn more?
(Other definitions for crown jewels that I've seen before include "Valuable regalia" , "Tower of London sparklers" , "national treasures" , "held in the Tower of London" , "Monarch's regalia" .)