谨

谨 = 堇 + 讠 : Joan of Arc (ji) is reading a warning on an advertising column (讠) in the encampment ((e)n3). The warning says that she should be very careful (谨) about violet dirt (堇) which tends to fall off the ceiling. While Joan of Arc reads the message, a big piece of violet dirt is about to fall on her head.

堇 = 土 + 革 : Joan of Arc (ji) is throwing violet (堇) clay (堇) and dirt (土) at the king's cow hide (革) in the encampment ((e)n3).

Mnemonic symbol: this character looks like a big "i" (like in information), and I'll represent it by an advertising column. Maud Younger (y) gives a speech (讠) standing on top of an advertising column (讠) in the anthill's kitchen (an2).