Vessel going from side to side (5)
I believe the answer is:
'vessel' is the definition.
(I know that ferry is a type of boat)
'going from side to side' is the wordplay.
I cannot quite understand how this works, but
'from' could be 'e' (I've seen this in other clues) and 'e' is present in the answer.
'side' could be 'r' (abbreviation for right) and 'r' is located in the answer.
'to side' could be 'r' (abbreviation for right) and 'r' is found in the answer.
The remaining letters 'fy' is a valid word which might be clued in a way I don't see.
This may be the basis of the clue (or it may be nonsense).
Can you help me to learn more?
(Other definitions for ferry that I've seen before include "Carry by boat" , "Passenger ship travelling regularly over a short distance" , "Boat that provides transport over stretch of water" , "Boat across e.g. English Channel" , "Transport boat that plies regularly" .)