ruthless; fierce; ferocious; determined; resolute; to harden (one's heart); old variant of 很[hen3]

callous; heartless; to resolve (to do sth); firm resolve (as in 下狠心[xia4 hen3 xin1])

vicious; malicious; savage

to exert all one's force; all-out effort; CL:股[gu3]

exerting all one's strength