This is a short post just for fun. Here are some of the hardest kanji I’ve run into over my years studying Japanese. If you learn these words, you can be confident in the knowledge that you’ve already tackled the hardest kanji (that I can think of).
躊躇（ちゅう・ちょ） – hesitation
朦朧（もう・ろう） – dim, hazy
憂鬱（ゆう・うつ） – depression
瀟洒（しょう・しゃ） – elegant; trim
The most difficult kanji is 「鬱」 with a total of 29 strokes. With a sufficiently small font size, it just looks like a black scribbly thing.
And here is my vote for the sneakiest kanji ever.
曰く（いわ・く） – to say