Making noise or wearing away (7)
I believe the answer is:
erosion
'wearing away' is the definition.
(synonyms)
'making noise or' is the wordplay.
'making' indicates anagramming the letters.
'noise'+'or'='noiseor'
'noiseor' anagrammed gives 'EROSION'.
(Other definitions for erosion that I've seen before include "The gradual wearing away by weather" , "A wearing away as of rock by water" , "The wearing away as by wind or water" , "Process of wearing away, by water or time" , "Mechanical process of wearing something down" .)