Both Uses

arbitrary
in
William Wilson
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My namesake alone, of those who in school phraseology constituted "our set," presumed to compete with me in the studies of the class—in the sports and broils of the play-ground—to refuse implicit belief in my assertions, and submission to my will—indeed, to interfere with my arbitrary dictation in any respect whatsoever.†
*

arbitrary = based on chance or impulse
The sentiment of deep awe with which I habitually regarded the elevated character, the majestic wisdom, the apparent omnipresence and omnipotence of Wilson, added to a feeling of even terror, with which certain other traits in his nature and assumptions inspired me, had operated, hitherto, to impress me with an idea of my own utter weakness and helplessness, and to suggest an implicit, although bitterly reluctant submission to his arbitrary will.†

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)