Fun fun fun

The kanji 楽, fun, easy, was originally written 樂 and is supposed to be derived from a pictograph of some bells hanging from a tree. It was borrowed for its sound for the modern meaning, and it appears in a few other kanji. See if you can guess what these characters mean.

• 薬　grass + fun
• 擽　hand + fun
• 轢　car + fun

薬　drugs, medicine
This is a fairly basic kanji, and it's easy to remember the meaning. The other two characters are quite rare.
薬　くすり　drugs, medicine

擽　to tickle
As far as I can tell, the 樂 part is only there as a phonetic guide, but the constituent parts fit the meaning so well I'm surprised this character isn't better known.
擽る　くすぐ・る　to tickle

轢　to run over
Car fun! Joy riding? Well, one of the words this kanji is used in is  轢死. Car fun death? In the world of kanji, the most fun you can have in your car is to run somebody over. How macabre.
轢く　ひ・く　to run over


As gruesome as kanji gets, nobody really thinks that running somebody over is a barrel of laughs. The kanji 楽 comes from a pictograph of a tree with a lot of chrysalises, which referred to the saw-tooth oak. The chrysalises survived as the 幺 in the old character, today simplified as four dashes. Later an acorn was added, and this now is the most prominent part 白.

Then the character was borrowed for its sound. This is a very common phenomenon in kanji; the original meaning is completely lost, as its used for a more common homonym. In this case, the word for 'pleasure' or 'comfort'. To get the meaning of saw-tooth oak, tree is added to the left side 櫟, to tell the reader 'this is the tree 樂, I'm not using it to mean "fun" here'.

轢 is using 楽 for its sound, as they had similar pronunciations in Chinese, and, by a convoluted word association: a tree with acorns　→　acorns　→　small objects → small stones, it had the meaning of crushing small stones as you drive over them.