Smooth shift a lot of obtuse guesswork (5)
I believe the answer is:
segue
'smooth shift' is the definition.
(I've seen this in another clue)
'a lot of obtuse guesswork' is the wordplay.
'a lot of' indicates the answer is hidden within the clue (I've seen 'a lot' mean this (a lot of the letters from the clue)).
'SEGUE' can be found hidden inside 'obtuse guesswork'.
(Other definitions for segue that I've seen before include "Play on" , "carry on" , "Smooth musical transition" , "Follow smoothly on" , "Change smoothly from one thing to another" .)