Assassin, Cutthroat, Gunman and Bravo designate a murderer or one who can be hired to murder in cold blood.
Assassin stresses secrecy and treachery in operation.
- like assassins, these destructive animals do their work in the dark
It is chiefly applied to murderers of important personages.
- tyrants always live in dread of assassins
- Revolutions breed assassins
Cutthroat and gunman usually designate professional hired murderers.
Cutthroat is chiefly literary or merely figurative because daggers and knives are no longer the weapons usually employed by such criminals, but the word still commonly suggests brutal methods of murder.
- I am a soldier, sir, and not a cutthroat
—Froude
Gunman is used somewhat more broadly than the foregoing terms since it may denote not only one who murders with a firearm but one (as a gangster) who goes armed and is prepared to shoot to prevent interference with his criminal activities or at the orders of a leader or employer.
Basically a bravo is a blustering unscrupulous ruffian or desperado.
- a few halfhearted catcalls from young bravos of the opposing party
—Barker
The word is especially applicable in an historical situation and commonly implies a venality sufficient to perform murder for hire.
- unfolds all of seventeenth-century Italy and its dramas—its predatory noblemen, its murderous bravos
—Rob - the hired bravos who defend the tyrant’s throne
-Shelley