Not royal; in particular, not appropriate for a royal.(adjective)
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Use "unroyal" in a sentence
"The numerous royal commissions have been quite 'unroyal' and a waste of useful resources."
"Ignoring his rather unroyal appearance, Rennek marched through the castle in the hopes of finding someone to lash out at."
"Their starter home: They may aspire to a normal and unroyal life, but the newlyweds 'home will be the grandest of any of Queen Elizabeth's offspring."