Publicity, so to speak (3)
I believe the answer is:
ink
'publicity so to speak' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Other definitions for ink that I've seen before include "Fluid from cuttlefish" , "Writing medium" , "Pen fluid" , "form of writing" , "It is ejected by cuttlefish" .)