形容詞 rightful:

1. legally valid
2. having a legally established claim
   同義詞：true, lawful

1. He has a rightful claim to the property; it was his mother's.
   這份財產原是他母親的，他具有合法所有權。
2. He was cheated (out) of his rightful inheritance.
   他依法應得的遺產被人騙走了。
3. I am the rightful owner of this car.
   我是這輛新車的合法主人。
4. What he said is a rightful claim.
   他所說的是正當的要求。

right.ful

adj.（形容詞）
Right or proper; just.
正確的，正當的；公正的
Having a just or proper claim:
合法的：具有合法或正當要求的：
例句：
Return this dog to its rightful owner.
將這條狗歸還其合法主人

Held or owned by just or proper claim:
依法享有權利的：以合法或正當的要求持有或擁有的：
例句：
This land is my rightful property.
這塊地產是我合法擁有的財產

【引伸】
right.fully
adv.（副詞）
right.fulness
n.（名詞）