Dubious moment when leader disappears (4)
I believe the answer is:
iffy
'dubious' is the definition.
(I've seen this before)
'moment when leader disappears' is the wordplay.
I cannot quite see how this works, but
'when' could be 'if' and 'if' is found in the answer.
'leader' could be 'f' (I have seen 'German leader ' mean 'f' so perhaps 'leader' could also mean 'f') and 'f' is located in the answer.
A single letter 'y' remains which might be clued in a way I don't understand.
This may be the basis of the clue (or it may be nonsense).
Can you help me to learn more?
(Other definitions for iffy that I've seen before include "Chancy, suspect" , "Full of uncertainty" , "Doubtful, not definite" , "Uncertain (colloq.)" , "Questionable (inf)" .)