So "Asian" apparently isn't an acceptable answer, but "wigga" is?  Huh?

Asian is a noun so correctly rejected. wigga appears to be relatively new word.

Um well there are plenty of nouns that are accepted...the solution yesterday "PIZZA" is a noun...I guess you mean proper noun?  But really "Asian" is more of an adjective than anything.  Just seems odd.  Regardless I'd love to hear an explanation of why "wigga" is acceptable.

It's probably just on the much less curated list of words that are accepted as guesses but not solutions. I highly doubt it's in the solutions list.

Given that Asian is always capitalized, it understandably never made it on either list. Proper nouns/adjectives are easy to remove.

Um yes my bad, I meant Asian is a proper noun. And yeah wigga definitely should not be in the answers list.

Whether Asian is a proper noun or an adjective can only really be determined by the context. Since there is no context here, perhaps proper noun is assumed. If Asian had been allowed, perhaps there would be a topic about why a proper noun was allowed, so the developer is in a no win situation.

Also, may just be coincidence, but wigga appears in the Scrabble dictionary and Asian does not.

Huh, I have no idea how it got in the word list since Wiktionary is the only source that registers it. 

It will be removed next time I update the application.