frivolous
unsettled
unsteady
volatile
egotistic
feather-headed
featherbrained
galant
hoydenish
ill-grounded
laser-cooled
loose-lipped
modestest
phantasmic
piddle
roundabout
true-born
true-to-life
unadvised
unaspiring
unconscientious
unconsolable
unedifying
unmystical
unobservant
unsteadfast
vagarious