Instruct, coach (5)
I believe the answer is:
train
I believe this is a double definition.
'instruct' is the first definition.
(I know that instruct is the is a more specific form of the action of train.)
'coach' is the second definition.
(both can mean to instruct a sportsperson)
(Other definitions for train that I've seen before include "Learn a skill etc. through practice" , "Succession of carriages" , "Try to get fit" , "Help (someone) to become fit" , "tutor" .)