耗
モウ, コウ, カウ
decrease
JLPT1 G7 S10 F5000
Once written
秏
, which is
禾
grain/rice +
毛
# (fine objects) → fine particles of grain, decreased in size by polishing → *decrease*; *decline*; *wear down*.
禾
was later replaced by
耒
plow.
[Full Kanji Etymology List]