rightfully

From Middle English ryghtefully, equivalent to rightful +‎ -ly.

rightfully (comparative more rightfully, superlative most rightfully)

1. In accordance with what is right or just; fairly.
   • The only purpose for which power can be rightfully exercised over any member of a civilized community, against his will, is to prevent harm to others. His own good, either physical or moral, is not sufficient warrant. -- John Stuart Mill
2. Rightly, correctly.
   • 1590, Edmund Spenser, The Faerie Queene, II.viii:

     Ne euer will it breake, ne euer bend. / Wherefore Morddure it rightfully is hight.