Dodgy moment, not the first (4)
I believe the answer is:
iffy
'dodgy' is the definition.
(I've seen this before)
'moment not the first' is the wordplay.
'moment' becomes 'jiffy' (I've seen this before).
'not the first' means to remove the first letter.
'jiffy' with its initial letter taken away is 'IFFY'.
(Other definitions for iffy that I've seen before include "Not certain, doubtful" , "Chancy, suspect" , "Uncertain (colloq.)" , "Doubtful, not definite" , "Sixth (RU) Nation" .)