Take a course in seamanship? (5)
I believe the answer is:
'take' is the definition.
The answer and definition can be both to do with motion as well as being verbs in their base form.
Perhaps you can see an association between them that I don't see?
'a course in seamanship?' is the wordplay.
'a course' becomes 'e'.
'in' means one lot of letters goes inside another.
'seamanship?' becomes 'ster' (I am not sure about this - if you are sure you should believe this answer much more).
'e' going into 'ster' is 'STEER'.
Can you help me to learn more?
(Other definitions for steer that I've seen before include "bovine individual?" , "piece of advice" , "Cattle - guide" , "Cattle - drive" , "Guide (eg, a ship)" .)