【Due】 , 【rightful】 , 【condign】 are comparable when they mean being in accordance with what is just and appropriate.

【Due】 , which basically means owed or owing as a debt, carries over in the sense here considered a strong implication that the thing so described is grounded upon an obligation, duty, or debt which should not or cannot be ignored; thus, one who takes 【due】 precautions uses the care that is required by his obligation to look out for his own or for others′ safety or well-being; one who has a 【due】  sense of another person′s rights accords to that person all that belongs to him by natural or moral right; one who has  【due】 respect for the law observes the individual laws as the duty of a responsible citizen.

Often the term implies little more than an accordance with what is right, reasonable, or necessary.

【Rightful】 carries a much stronger and more consistent implication than 【due】  of a ground in right and justice, and usually suggests a moral or legal claim.

【Condign】 applies to something that is distinctly deserved or merited and usually something that neither exceeds nor falls below one′s deserts or merits; the term is used chiefly of punishment, often with the implication of severity.