Elevator pioneer (4)
I believe the answer is:
otis
'elevator pioneer' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for otis that I've seen before include "regretful lady" , "Lift man" , "Place of worship; side part of head" , "---- Redding, 1941-67, soul singer" , "Regretful miss" .)