Man's one correcting lies (4)
I believe the answer is:
isle
'man's one' is the definition.
(I've seen this before)
'correcting lies' is the wordplay.
'correcting' indicates an anagram (the order of letters must be corrected).
'lies' anagrammed gives 'ISLE'.
(Other definitions for isle that I've seen before include "eg Man, Dogs" , "Land cut off by water" , "Isolated land" , "Ireland, perhaps" , "small piece of land" .)