軽
ケイ, かる.い, かろ.やか, かろ.んじる
lightly, trifling, unimportant
JLPT2 G3 S12 F790
As per
巠
# as described in
徑
(extensive) + 車 vehicle → long, lightweight vehicle → *light*; *lessen/lighten*; *make light of*.
[Full Kanji Etymology List]