勇
ユウ, いさ.む, お, はや

courage, cheer up, be in high spirits, bravery, heroism

JLPT2 G4 S9 F1319

An abbreviated form# of 甬 (run through) + 力 power/energy → stamp the ground energetically, as though to run through it → *spirited*; *lively* → *brave*; *courageous*.

[Full Kanji Etymology List]