A confused disordered jumble of things.
Background echoes, from clouds etc., on a radar or sonar screen.
To utter words hurriedly, especially (but not exclusively) as a speech disorder (compare cluttering).
To fill something with clutter.
To make a confused noise; to bustle.
A situation whereby several problems come together and make everything worse.
A powerful hurricane or other major weather disturbance, especially as produced by a combination of meteorological conditions.