fickle
US /ˈfɪk.əl/
UK /ˈfɪk.əl/

1.
inconstante, volúvel
changing frequently, especially as regards one's loyalties, interests, or affection
:
•
The weather here is notoriously fickle.
O tempo aqui é notoriamente inconstante.
•
She's very fickle, one day she loves you, the next she hates you.
Ela é muito volúvel, um dia ela te ama, no outro ela te odeia.