Like garage floors, often (4)
I believe the answer is:
oily
'like garage floors often' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for oily that I've seen before include "Smooth, ingratiating" , "covered in grease" , "Oleaginous" , "Smoothly ingratiating" , "Smooth; like lubricant" .)