Fearsome, though again inviting uncertainty? (11)

'fearsome' is the definition.
(I know that fearsome can be written as redoubtable)

'again inviting uncertainty?' is the wordplay.
I cannot really see how this works, but
'again' could be 're' (prefix meaning 'again') and 're' is found in the answer.
'uncertainty?' could be 'doubt' (doubt is a kind of uncertainty) and 'doubt' is found in the answer.
The remaining letters 'able' 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).

'though' acts as a link.