unpredictable (adj.)

• accidental
• adrift
• adventitious
• afloat
• agnostic
• aleatory
• alternating
• ambiguous
• amorphous
• capricious
• casual
• causeless
• chance
• chancy
• changeable
• changeful
• contingent
• coquettish
• desultory
• dicey
• dizzy
• doubtful
• doubting
• dubious
• eccentric
• equivocal
• erratic
• extraordinary
• faddish
• fatal
• fickle
• fitful
• flickering
• flighty
• flirtatious
• fluctuating
• fluky
• fortuitous
• freakish
• giddy
• hesitant
• hesitating
• iffy
• impetuous
• improbable
• impulsive
• incalculable
• incidental
• inconsistent
• inconstant
• indecisive
• indeterminate
• infirm
• insecure
• irregular
• irresolute
• irresponsible
• light
• mazy
• mercurial
• moody
• out-of-the-way
• polysemous
• quicksilver
• rambling
• restless
• risky
• rocky
• roving
• scatterbrained
• shaky
• shapeless
• shifting
• shifty
• skeptical
• skittish
• spasmodic
• spineless
• sudden
• tottery
• touch-and-go
• treacherous
• unaccountable
• unannounced
• unanticipated
• uncaused
• uncertain
• uncontrolled
• unconvinced
• undependable
• undetermined
• undisciplined
• unexpected
• unfixed
• unforeseeable
• unforeseen
• unhealthy
• unheralded
• unlooked-for
• unpersuaded
• unpredicted
• unprovable
• unreliable
• unrestrained
• unsafe
• unsettled
• unsound
• unstable
• unsteady
• unsure
• untrustworthy
• unverifiable
• vacillating
• vagrant
• variable
• versatile
• volatile
• wandering
• wanton
• wavering
• wavy
• wayward
• whimsical
• wishy-washy