For comparison, is maybe over a mile (6)
I believe the answer is:
simile
'for comparison' is the definition.
(simile is a kind of comparison)
'is maybe over a mile' is the wordplay.
'maybe' indicates an anagram.
'over' means one lot of letters go next to another (in a down clue, some letters go over others).
'is' with letters rearranged gives 'si'.
'si'+'mile'='SIMILE'
(Other definitions for simile that I've seen before include "Figure of speech expressing resemblance between different things" , "Figure of speech used in making comparisons" , "Lies I'm finding in figure of speech" , "as pleased as Punch perhaps?" , "as easy as pie, perhaps" .)