/ ˈfɪkl; NAmE / adjective ( disapproving )
1.
changing often and suddenly :
The weather here is notoriously fickle.
the fickle world of fashion
2.
( of a person ) often changing their mind in an unreasonable way so that you cannot rely on them :
a fickle friend
► fickle·ness noun [ U ]:
the fickleness of the English climate
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WORD ORIGIN
Old English ficol deceitful , of Germanic origin.