unreliable (adj.)
- adrift
- afloat
- alternating
- amorphous
- capricious
- changeable
- changeful
- coquettish
- dangerous
- desultory
- disreputable
- dizzy
- doubtful
- dubious
- eccentric
- erratic
- faddish
- faithless
- false
- fickle
- fitful
- flickering
- flighty
- flimsy
- flirtatious
- fluctuating
- fly-by-night
- freakish
- garbled
- giddy
- hazardous
- impetuous
- impulsive
- inaccurate
- inauthentic
- inconsistent
- inconstant
- indecisive
- inexact
- infirm
- insecure
- insubstantial
- irregular
- irresolute
- irresponsible
- light
- mazy
- mercurial
- moody
- perfidious
- perilous
- precarious
- provisional
- questionable
- quicksilver
- rambling
- restless
- risky
- rocky
- roving
- scatterbrained
- shaky
- shapeless
- shifting
- shifty
- skittish
- slick
- slippery
- spasmodic
- spineless
- spurious
- temporary
- tentative
- ticklish
- tottery
- treacherous
- tricky
- unaccountable
- unassured
- unauthentic
- uncertain
- uncontrolled
- undependable
- undisciplined
- unfaithful
- unfixed
- unfounded
- unhealthy
- unpredictable
- unrestrained
- unsafe
- unsettled
- unsound
- unstable
- unsteady
- unsubstantial
- unsure
- untrue
- untrustworthy
- untrusty
- vacillating
- vagrant
- variable
- versatile
- volatile
- wandering
- wanton
- wavering
- wavy
- wayward
- weak
- whimsical
- wishy-washy
- workaday
