Possibly cyclist will suggest an additional clause (5)
I believe the answer is:
rider
This clue might be a double definition.
'possibly cyclist' is the first definition.
(I know that cyclist is a type of pedaler)
'additional clause' is the second definition.
(additional clause on a contract or agreement)
'will suggest an' acts as a link.
This may not be right. Some or all of it may belong to one of the definitions.
Can you help me to learn more?
(Other definitions for rider that I've seen before include "it may be added" , "Person in the saddle" , "One on horse or bike" , "Passenger" , "Proviso in a legal document" .)