There is a [list of resources][1], including [dictionaries][2], on English Language and Usage Meta that you may find helpful.

To answer your question about Wiktionary: as long as the definition is accurate, I wouldn't criticize or downvote an answer for citing this source. However, in general I think other dictionaries are perceived as more authoritative, so for any definition that seems like it might be controversial, I would seek another source.

  [1]: https://english.meta.stackexchange.com/questions/2573/what-good-reference-works-on-english-are-available
  [2]: https://english.meta.stackexchange.com/a/2574/77227