Why does "adh" need the definitive particle here, whereas "ead" (jealousy) and others do not need the definitive particle?
An older meaning of ádh is “fate”; perhaps its current usage, which most often has an article, is connected somehow to that.
No — if the sentence’s an were the intensifying prefix rather than the definite article, then there would be a hyphen after an. But since an-ádh in Tá an-ádh ort is an abstract noun used in a general sense, it would still need to have a definite article, so Tá an an-ádh ort would translate “You are very lucky”.
Thanks for your prompt response. I appreciate your tips, clarifications, etc. You and a few others really do a good job of providing assistance in learning this fascinating, but difficult language (and I have studied many).
It marks "you have the luck" incorrect. Would that be "tá an t-ádh ort agat"