Justifiable a. : Capable of being justified, or shown to be just.

Example:
What is the only Justifiable reason for speeding on the freeway?

Taxonomy
justifiable homicide, states, arrest, killing, suspect, homicide, excuses, law, murder, offense, arrestor, grievous bodily harm, United States, defense, self-defense, victim, free encyclopedia, criminal homicide.

Defination from the web:
... Hence, in eighteenth century English law, it was considered a justifiable homicide if a husband killed a man "ravishing" or raping his wife (Blackstone, Wm. ...