I can understand the link between 閒 and 間/间, being the empty spaces where moonlight or sunlight can shine through the doors --> empty space. But how did this 閒 also end up becoming similar to 閑/闲? And how does a "moon behind the door" or "tree behind the door" correlate with the meaning of "free time"?
PY xián (or jiān, jiàn)
閒 originally depicted a door (門), such that the moon (月) could be seen through a crack in the door, indicating the original meaning “crack, split.”
In 閒, 門 “a double-sided door; door, gate; opening” is a form component, pointing to the original meaning “crack, split.”
In 閒, 月 “the moon” is a form component.
1 (orig.) crack, split
2 ○ leisure, free time
1 → room, space (same as 間)
2 ⇒ duration of time
1 → space in between (same as 間)
2 ⇒ separate
The reference they give:
It looks like the entry in Xinzheng actually begins on page 836. Here is the combined original
The idea of free time is another phonetic loan again. Seems a bit climatic, I know.
Here is p. 1043《字源》talking about 閑
The last sentence is quite interesting.
- 閑 was originally a character that meant, "fencing around a door."
- 閒 was orignally a character that meant, "crack/split."
- 閑 was borrowed for it's sound to indicate, "free time."
- 間 has derivative meanings of "room/space" from the idea of "crack/split."