He pulls himself backwards (5)
I believe the answer is:
rower
'he pulls himself backwards' is the definition.
The answer is a person as well as being a singular noun. This is suggested by the definition.
This is all the clue.
Can you help me to learn more?
(Other definitions for rower that I've seen before include "Might one argue" , "one pulling a blade?" , "Waterman" , "Person using 9" , "Sportsperson" .)