Synonyms of arbitrary in English:

arbitrary


See definition of arbitrary

adjective

1‘an arbitrary decision from the top’

SYNONYMS
capricious, whimsical, random, chance, erratic, unpredictable, inconsistent, wild, hit-or-miss, haphazard, casual
unmotivated, motiveless, unreasoned, unreasonable, unsupported, irrational, illogical, groundless, unjustifiable, unjustified, wanton
discretionary, personal, subjective
rare discretional
ANTONYMS

rational, reasoned

2‘the arbitrary power of a prince’

SYNONYMS
despotic, tyrannical, tyrannous, peremptory, summary, autocratic, dictatorial, authoritarian, draconian, autarchic, anti-democratic
oppressive, repressive, undemocratic, illiberal
imperious, domineering, high-handed
absolute, uncontrolled, unlimited, unrestrained
ANTONYMS

democratic, accountable