Meaning of “flutter” - Learner’s Dictionary

flutter

verb uk us /ˈflʌtər/

[ I, T ] to move quickly and gently up and down or from side to side in the air, or to make something move in this way:

The flag was fluttering in the breeze.
flutter about/around/down, etc

to move somewhere quickly and gently, usually without any particular purpose:

There were several moths fluttering around the light.

(Definition of “flutter verb” from the Cambridge Learner’s Dictionary © Cambridge University Press)