the only time i saw this word used is from a 70's episode of Dr Who called The ark in space, where a female character says "He has the authority to initiate condign action"

Now we know

appropriate, condign, conscientious, correct, deserved, due, equitable, ethical, fitting, good, honest, honorable, justifiable, lawful, legal, legitimate, merited, moral, proper, requisite, righteous, rightful, scrupulous, stand-up, suitable, true, upright, virtuous.

According to SOWPODS (the combination of Scrabble dictionaries used around the world) there are 3 words with the pattern C---IG-. That is, seven letter words with 1st letter C and 5th letter I and 6th letter G. In alphabetical order, they are:

condign

consign

coreign

The act of retributing; repayment., That which is given in repayment or compensation; return suitable to the merits or deserts of, as an action; commonly, condign punishment for evil or wrong., Specifically, reward and punishment, as distributed at the general judgment.

According to SOWPODS (the combination of Scrabble dictionaries used around the world) there are 5 words with the pattern ---DIG-. That is, seven letter words with 4th letter D and 5th letter I and 6th letter G. In alphabetical order, they are:

condign

mendigo

prodigy

wendigo

windigo