adjective
1.
Synonyms: arbitrary 1, erratic, freakish, vagarious, wayward, whimsical, whimsied
2.
Synonyms: inconstant 1, changeable, fickle, lubricious, mercurial, temperamental, ticklish, unstable, variable, volatile
Related Word: humorsome, moody; effervescent
Contrasted words: constant, steady
Antonyms: steadfast
3.
Synonyms: uncertain 1, chancy, dicey, erratic, fluctuant, iffy, incalculable, unpredictable, whimsical