ハク, せま.る, さこ, せ, せこ, はさ, はさま, はざま
urge, force, imminent, spur on
JLPT1 G7 S8 F773
As per 白# (scatter) + 辵 movement → *apply pressure* in approaching enemies, causing them to scatter → *approach*/*draw near* in pressuring → *be imminent*; *urge*; *press* (a person to do something).
[Full Kanji Etymology List]