clutter

nouns

a confused multitude of things
clutter, fuddle, jumble, mare's nest, muddle, smother, welter
unwanted echoes that interfere with the observation of signals on a radar screen
clutter
is a type of (narrower)
an electronic signal that has been reflected back to the radar antenna; contains information about the location and distance of the reflecting object
radar echo
is a type of (narrower)
electrical or acoustic activity that can disturb communication
disturbance, interference, noise

verbs

fill a space in a disorderly way
clutter, clutter up
antonym
unclutter