Both Uses

arbitrary
in
The Other Wes Moore
(Edited)

You could see it in the people in the neighborhood, intimidated by the drug dealers and gangs, harassed by the petty crime of the crackheads, and frightened by the sometimes arbitrary and aggressive behavior of the cops themselves.
p. 81.8

arbitrary = based on chance or impulse
Having an advocate on the inside—someone who had gotten to know me and understood my story on a personal level—had obviously helped. It made me think deeply about the way privilege and preference work in the world, and how many kids who didn't have "luck" like mine in this instance would find themselves forever outside the ring of power and prestige. So many opportunities in this country are apportioned in this arbitrary and miserly way, distributed to those who already have the benefit of a privileged legacy.
p. 161.1 *

arbitrary = unfair (based on chance)

Definitions:

(1) (arbitrary)
based on chance or impulse (rather than upon reasoning, consistent rules, or a proper sense of fairness)
(2) (meaning too rare to warrant focus)