Instructor replaced cheat with hesitation (7)
I believe the answer is:
teacher
'instructor' is the definition.
(I know that instructor can be written as teacher)
'replaced cheat with hesitation' is the wordplay.
'replaced' is an anagram indicator.
'with' means one lot of letters go next to another.
'hesitation' becomes 'er' (sound made while hesitating - um, er).
'cheat' with letters rearranged gives 'teach'.
'teach'+'er'='TEACHER'
(Other definitions for teacher that I've seen before include "Member of school staff" , "'Instructor, educator (7)'" , "One who educates" , "Chips, perhaps?" , "The race (anag.)" .)