This word is acceptable for play in the US & UK dictionaries that are being used in the following games:

• Lexulous
• Wordscraper
• Wordosaur

adj. Reigning; ruling: a queen regnant.

adj. Predominant.

adj. Widespread; prevalent.

adj. Exercising regal authority; reigning.

adj. Having the chief power; ruling; predominant; prevalent.

Reigning; exercising regal authority by hereditary right.

Ruling; predominant; prevalent; having the chief power.

adj. exercising power or authority

""regnant" to be altogether satisfactory; and there are many similar extravagances and inaccuracies."

powerful   

queen regnant   

reigning    ruling    predominant    prevalent    controlling   

regnal    latifah    full-orbed    proprietorships    pain-killing    well-brought-up    starships'    hemotoxic    fire-lizard    ghastliest