細
サイ, ほそ.い, ほそ.る, こま.か, こま.かい
dainty, get thin, taper, slender, narrow
JLPT2 G2 S11 F537
Variant form of
緦
fine cloth → *fine*; *slight*; *thin*; *slender*; *narrow* → *detailed*; *dwindle*.
[Full Kanji Etymology List]