ス, シュ, すべから.く, すべし, ひげ, まつ, もち.いる, もと.める, もとむ, ぞ
ought, by all means, necessarily
JLPT1 G7 S12 F1339
A depiction of an old man with a long, soft *beard*. The present form is 彡 pattern (here suggesting beard whiskers) + 頁 head. *Necessary*, *should* and *ought* are borrowed meanings.
[Full Kanji Etymology List]