古
コ, ふる.い, ふる, ふる.す, ふゆ
old
JLPT4 G2 S5 F509
The relevant oracle bone form of
古
combines
口
mouth + an object filling it → expectorate *old*, *dried out*, *hard* food → *dry up*; *stale* → *used*; *old-fashioned*.
[Full Kanji Etymology List]