fickle

adjectives

marked by erratic changeableness in affections or attachments
"fickle friends"; "a flirt's volatile affections"
fickle, volatile
is derived from
fickleness
liable to sudden unpredictable change
"erratic behavior"; "fickle weather"; "mercurial twists of temperament"; "a quicksilver character, cool and willful at one moment, utterly fragile the next"
erratic, fickle, mercurial, quicksilver
is derived from
fickleness