Fickle means changing loyalties and moods without warning. Fickle fans, the fickle public, fickle weather.
It is a criticism of unreliability rather than of judgement: fickle affections switch for no reason anybody can follow. It attaches to crowds, fashion, fortune and the British weather. Fickle fortune is an old fixed phrase. Note fickleness; and that the word once meant deceitful rather than merely changeable, which is a harder charge and closer to its Old English sense.
1adjectivefickleChanging loyalties and moods without warning.
“Football fans can be fickle, cheering a player one week and booing him the next.”
synonyms: capricious, inconstant
fickle is a quality of inconstancy.
Old English ficol meant deceitful or tricky. The sense softened from actively deceiving to merely unreliable, which is a fairly common direction for a word to travel.
Old English
ficol — fickle, cunning, tricky, deceitful
Middle English
fikil
English, today
fickle
From Middle English fikil, fikel, from Old English ficol (“fickle, cunning, tricky, deceitful”), equivalent to fike + le. More at fike.
Etymology from Wiktionary, CC BY-SA