Distances formed from slime (5)
I believe the answer is:
miles
'distances' is the definition.
(I've seen this in another clue)
'from slime' is the wordplay.
'from' indicates an anagram (the anagram comes from the same letters).
'slime' anagrammed gives 'MILES'.
'formed' is the link.
(Other definitions for miles that I've seen before include "a long way" , "Imperial units of length" , "Distance units" , "'But I have promises to keep, and . . . . . to go before I sleep' (Frost)" .)