Work takes time: slick stuff! (4)
I believe the answer is:
toil
'work' is the definition.
(I know that toil is a type of work)
'time slick stuff' is the wordplay.
'time' becomes 't' (abbreviation).
'slick stuff' becomes 'oil' (I've seen this in another clue).
't'+'oil'='TOIL'
'takes' acts as a link.
(Other definitions for toil that I've seen before include "Manual labour" , "Work hard, labour" , "Drudgery" , "Hard physical work" , "Work extremely hard" .)