fickle
adjective
1. quick to change one’s opinion or allegiance; insincere; not loyal or reliable.
- fickle friends
Similar word(s): inconstant, volatile
2. liable to sudden unpredictable change
- fickle weather
Similar word(s): changeable, changeful, erratic, mercurial, quicksilver
verb
1. (transitive) To deceive, flatter.
2. (transitive, Britain dialectal) To puzzle, perplex, nonplus.