IPA: /ˈraɪt.fəl.i/
KK: /ˈraɪtfəli/
In a way that is fair or just; in a manner that is correct or appropriate.
She was rightfully proud of her achievements after all the hard work she put in.
Rightfully → It is formed from "right" (from Old English "riht", meaning correct or just) and "-fully" (meaning in a manner full of). The word "rightfully" means in a manner that is just or correct.
Think of doing something in a way that is 'just' or 'correct' ('right') and 'full of' that quality ('-fully'). This helps you remember that 'rightfully' means acting in a just manner.