不逞之徒

不

bù

no; not so

逞

chěng

to show off

之

zhī

(possessive particle, literary equivalent of 的[de5])

徒

tú

(bound form) disciple; apprentice; believer; (derog.) wrongdoer (as in 騙徒|骗徒[pian4 tu2] "swindler" or 叛徒[pan4 tu2] "traitor" etc)