\Right"ful\, a.
1. Righteous; upright; just; good; -- said of persons. [Obs.]
   --Chaucer.

2. Consonant to justice; just; as, a rightful cause.

3. Having the right or just claim according to established
   laws; being or holding by right; as, the rightful heir to
   a throne or an estate; a rightful king.

4. Belonging, held, or possessed by right, or by just claim;
   as, a rightful inheritance; rightful authority.

Syn: Just; lawful; true; honest; equitable; proper.