We go about on pontoons and lighters at first (6)
I believe the answer is:
people
'pontoons and lighters at first' is the definition.
I can't tell whether this defines the answer.
'we go about' is the wordplay.
'we' becomes 'opl' (I can't explain this - if you can you should give a lot more credence to this answer).
'go' becomes 'pee' (both can mean to urinate).
'about' means one lot of letters goes inside another.
'opl' going into 'pee' is 'PEOPLE'.
'on' is the link.
Can you help me to learn more?
(Other definitions for people that I've seen before include "Humankind" , "Human beings in general" , "Mortals" , "Nation" , "Folk; citizens" .)