ボウ, モウ, いそが.しい, せわ.しい, おそ.れる, うれえるさま

busy, occupied, restless

JLPT3 G7 S6 F1475

As per # (obscure) + heart/emotions → obscure state of mind, on account of busyness or being pressed/hurried → *busy*.

[Full Kanji Etymology List]