Miles away from filth (5)
I believe the answer is:
slime
'filth' is the definition.
(I've seen this in another clue)
'miles away' is the wordplay.
'away' indicates anagramming the letters (letters move away from their original places).
'miles' with letters rearranged gives 'SLIME'.
'from' is the link.
(Other definitions for slime that I've seen before include "Moist slippery stuff" , "Gunge" , "Gunk" , "Nasty slippery stuff" , "Sludge, gloop" .)