arbitrary
https://gyazo.com/235b6f76d7710ac6f8c720db7a62f1a2
adjective
based on random choice or personal whim, rather than any reason or system:
任意の; 恣意的な, 独断的な; 気まぐれな
e.g. his mealtimes were entirely arbitrary.
(of power or a ruling body) unrestrained and autocratic in the use of authority:
〈政府などが〉専制的な, 独裁的な
e.g. arbitrary rule by King and bishops has been made impossible.
Mathematics (of a constant or other quantity) of unspecified value.
ORIGIN
late Middle English (in the sense ‘dependent on one's will or pleasure, discretionary’): from Latin arbitrarius, from arbiter ‘judge, supreme ruler’, perhaps influenced by French arbitraire.