Synonyms of arbitrary in English:

arbitrary


See US English definition of arbitrary

See UK English definition of arbitrary

See Spanish definition of arbitrario

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