Like the gases argon and xenon (5)
I believe the answer is:
noble
(Other definitions for noble that I've seen before include "Honourable ? aristocratic" , "old British coin" , "with a title?" , "Eminent" , "Honourable or of high rank" .)
I believe the answer is:
noble
(Other definitions for noble that I've seen before include "Honourable ? aristocratic" , "old British coin" , "with a title?" , "Eminent" , "Honourable or of high rank" .)