Platitude about rust I'm removing (6)
I believe the answer is:
truism
'platitude' is the definition.
(thesaurus)
'rust i'm removing' is the wordplay.
'removing' indicates anagramming the letters (moving the letters again).
'rust'+'im'='rustim'
'rustim' anagrammed gives 'TRUISM'.
'about' acts as a link.
(Other definitions for truism that I've seen before include "Obviously correct and verified statement" , "Statement or fact of obvious veracity" , "An obvious statement that says noting new or interesting" , "An obvious truth" , "Platitude, trite statement" .)