Synonyms for Cutthroat:

adj.

•hard-fought (adjective)
bloody.
•pitiless (adjective)
unsympathetic, brutal, unpitying, uncompassionate, cruel, unfeeling, hellish, pitiless, merciless, ruthless, bloodthirsty, hardhearted, barbaric, unforgiving, dog-eat-dog, Fiendish, inhumane, unmerciful, demoniac, stony.
•ruthless (adjective)
bloodthirsty, dog-eat-dog, pitiless, cruel, unprincipled, merciless.

n.

hit man, hired gun, serial killer, Assassin, death squad, lynch mob, hatchet man, hit squad. triggerman, manslayer, murderer, Massacrer, slayer, butcher, help, murderess, homicide, slaughterer. •cutthroat (noun)
bowelless, bloody, fierce, murderous, homicidal, merciless, unmerciful.
•evildoer (noun)
desperado, bad guy, vulture, monster, terrorist, ruffian, vandal, scoundrel, wrongdoer, crook, hoodlum, hooligan, snake, demon, evildoer, fiend, tough, law breaker, vampire, bully, gunman, criminal, tyrant, ogre, thug, brute, thief, viper.
•ruthless (noun)
unprincipled.
•unfair (noun)
unreasonable, partial, unequal, wrongful, unjustified, arbitrary, biased, unfair, one-sided, unjust.

Other synonyms:

Massacrer, slayer, murderess, slaughterer, triggerman. murderer, butcher, manslayer. homicide. bloody. •Other relevant words:
hatchet man, bowelless, hit man, unreasonable, butcher, fierce, manslayer, murderous, murderer, slaughterer, triggerman, slayer, bloody, Massacrer, homicide, unprincipled, Assassin, homicidal, murderess.

Usage examples for cutthroat

1. He's such a cutthroat – Tinker's Dam by Joseph Tinker

2. Deep and soft and soulful, though the man himself may have a soul like a bit of charred leather; velvety and tender, though they may belong to an out- and- out cutthroat expressive, eloquent even, though they are the eyes of a peon with no mind to speak of; night- black, and like the night filled with mystery. – The Bells of San Juan by Jackson Gregory