He doesn't know what to believe (8)

I believe the answer is:

agnostic

I'm a little stuck... Click here to teach me more about this clue!

'he doesn't know what to believe' is the definition.
The answer is a person as well as being a singular noun. This is suggested by the definition.

This is the entire clue.

Can you help me to learn more?

(Other definitions for agnostic that I've seen before include "One who is undecided" , "Coasting with unbeliever" , "Holding that knowledge of Supreme Being is impossible" , "One believing God is unknowable" , "Sceptic - unbelieving" .)

I've seen this clue in The Telegraph and The Globe and Mail.

Want a hint initially instead of a full solution? Install my app