1. Grammatical analysis is different: good luck is a combination of adjectives and nouns, which belongs to the usage of adjectives to modify nouns. Grammatically called noun phrase, it means that this phrase is a noun. Fortunately, there is no such usage.
2. Different meanings: Good luck means good luck, and I wish you (you) good luck. And good lucky has no specific meaning.
3, the usage is different: good luck is the correct usage. And good luck is wrong, there is no such phrase.