a disorderly heap or assemblage; litter: It's impossible to find anything in all this clutter.
6.
a state or condition of confusion.
7.
confused noise; clatter.
8.
an echo or echoes on a radar screen that do not come from the target and can be caused by such factors as atmospheric conditions, objects other than the target, chaff, and jamming of the radar signal.
Origin: 1550–60; variant of clotter (now obsolete), equivalent to clot + -er6