Religious pioneer, one going against the mainstream (4)
I believe the answer is:
eddy
This clue might be a double definition.
'religious pioneer' is the first definition.
The definition and answer can be both people as well as being singular nouns.
Perhaps they are linked in a way I don't understand?
'one going against the mainstream' is the second definition.
The answer is a person as well as being a singular noun. This is suggested by the definition.
Can you help me to learn more?
(Other definitions for eddy that I've seen before include "(Of fluid) circle round" , "Man" , "Whirl (in fluid)" , "Current running against the main stream, causes small whirlpool" , "Spin" .)