I step out on slope (5)
I believe the answer is:
piste
'slope' is the definition.
(I have seen 'slippery slope' mean 'piste' so perhaps 'slope' could also mean 'piste')
'i step out on' is the wordplay.
'out' indicates an anagram (out can mean wrong or inaccurate).
'on' indicates putting letters inside (as in clothing 'on' a person).
'step' is an anagram of 'pste'.
'i' placed inside 'pste' is 'PISTE'.
(Other definitions for piste that I've seen before include "Skiing course" , "slippery slope" , "A ski run of compacted snow" , "Ski trail" , "Winter sports course" .)