regnant
Reigning, ruling; currently holding power.
The people are now the State, their will is the regnant will, and that will has this characteristic — it loves principles, it hates compromises; and the principles it loves must be regulative, fit to be applied to the work and guidance of life.
Dominant; holding sway; having particular power or influence.
The doors of his temples were kept open in time of war, the time in which the ideas of contradiction and conflict are most naturally regnant.
of a monarch, ruling in one's own right; often contrasted with consort and dowager
Queen Elizabeth II reigned as queen regnant, unlike her mother Queen Elizabeth The Queen Mother.
Where it comes from
From Middle English regnant, reignant, from Middle French regnant, régnant, and its source, Latin rēgnāns, the present participle of regnāre.
Adapted from the Wiktionary entry regnant (CC BY-SA 4.0).