ficklest is fickle's Superlative

fickle

US [ˈfɪk(ə)l]
UK ['fɪk(ə)l]
  • adj.轻浮的
  • Web易变的;多变的;多情
Comparative Degree:fickler  Superlative:ficklest  
adj.
1.
轻浮的,反复无常的,易变的