[sì wú jì dàn]
act recklessly and care for nobody; act outrageously; afraid of nothing; behave in a disorderly manner without fear; fearing nothing; have no scrules at all; having no respect for anything; in an unscrupulous way; in the absence of all conventional restraints; no dread for anything; reckless and unbridled; run riot; scruple at nothing; stop at nothing; unbridled; brazenly; unscrupulously; without (any) scruple
make unbridled attacks
肆无忌惮地攻击
wanton aggression
肆无忌惮的入侵