A person who is indifferent or apathetic.
Indicating or reflecting a lack of concern or care.
Ambivalent; unconcerned; uninterested, apathetic.
Having no preference.
Mediocre (usually used negatively in modern usage).
Not making a difference; without significance or importance.
Being in the state of neutral equilibrium.
Used other than figuratively or idiomatically: see killer, instinct.
The natural inclination to do whatever is necessary to succeed (including extreme violence)