Teach, coach (5)
I believe the answer is:
train
I believe this is a double definition.
'teach' is the first definition.
(I know that train is a type of teach)
'coach' is the second definition.
(both can mean to instruct a sportsperson)
(Other definitions for train that I've seen before include "Suite; give practice (in)" , "Aim < to prepare < railway carriages" , "Prepare for public transport?" , "Tailpiece of bridal gown" , "tutor" .)