ETYM From Fit.
1. Intermittently stopping and starting; SYN. interrupted, off-and-on.
2. Occurring in spells and often abruptly; SYN. spasmodic.

1. Existing or enduring for a limited time only.
2. Not permanent; not lasting.

ETYM Latin inconstans: cf. French inconstant. Related to In- not, and Constant.
Likely to change frequently often without apparent or cogent reason; variable.

ETYM Latin labilis apt to slip, from labi to slip.
1. Open to change; liable to change.
2. (Chemistry, physics, biology) Readily undergoing change or breakdown.
3. Adaptable; unstable.
Liable to err or change; unstable.

1. Not settled or established
2. Not yet settled
3. Still in doubt

1. Disposed to psychological variability
2. Highly or violently reactive
3. Lacking stability or fixity or firmness

Subject to change or variation especially in behavior

ETYM French volatil, Latin volatilis, from volare to fly, perhaps akin to velox swift, Eng. velocity. Related to Volley.
1. Tending to vary often or widely.
2. (Chemistry) Evaporating readily at normal temperatures and pressures.

In a fitful manner.

Transiently, in a transitory manner, in a manner which is not permanent

Changeably; in a fickle manner