ハイ, せ, せい, そむ.く, そむ.ける
stature, height, back, behind, disobey, defy, go back on, rebel
JLPT3 G6 S9 F696
As per 北# (back) + 肉 flesh (to emphasize the physical aspect) → one's curved *back* → *height*. Also, *contrariness*; *go back on* (one's word); *go against*; *disobey*; *go/turn away* and *avert* (← turn one's back on), as well as *carry on one's back*.
[Full Kanji Etymology List]