Waves, wearing man's suit (8)
I believe the answer is:
tsunamis
'waves' is the definition.
(I know this)
'wearing man's suit' is the wordplay.
'wearing' indicates an anagram (wear can mean to become damaged).
'mans'+'suit'='manssuit'
'manssuit' anagrammed gives 'TSUNAMIS'.
(Other definitions for tsunamis that I've seen before include "Destructive sea waves" , "catastrophes" , "Violent sea waves" , "Huge destructive waves" , "Large ocean waves caused by underwater earthquakes" .)