What does "rightfully" mean?

In accordance with what is right or just.

What is a synonym for "rightfully"?

Common synonyms include: appropriately, appropriately, as is proper, as is right, by right, by rights.

/ˈɹaɪtfəli/ adv

adv ·Uncommon ·Advanced level

Adverb

1
In accordance with what is right or just.
"Near-synonym: fairly"
2
Rightly, correctly.
"Ne euer will it [King Arthur's sword] breake, ne euer bend. / Wherefore Morddure it rightfully is hight."

Adverb

"I only want what is rightfully mine."

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