adjective
fickle
FIK-uhl/ˈfɪkl/
Changing loyalties, interests, or opinions unpredictably.
The fickle hobbyist abandons unfinished knitting and painting to try the ukulele.

Etymology
Fickle probably comes from Old English ficol, meaning deceitful or cunning. Its earlier sense of treachery shifted toward inconstancy: changing loyalties or opinions rather than necessarily practicing deceit.
In context
The praise of others is fickle and entirely outside your command. Investing your sense of self in these externals is like building a house on shifting sand.
More examples
- Her fickle taste in music makes choosing a gift difficult.
- Voters are fickle, so an early lead guarantees nothing.
- My fickle brother has a new favorite hobby every month.
Forms
fickle · fickler · ficklest
fickleness noun — The tendency to change loyalties or interests unpredictably.
Similar words
- capricious
- Emphasizes sudden whims in decisions or behavior, not just loyalties.
- inconstant
- Emphasizes failure to remain loyal or steady over time.