As used by a writer thinking nothing? (3)
I believe the answer is:
ink
'as' is the definition.
The answer and definition can be both substances as well as being singular nouns.
Maybe you can see a link between them that I don't see?
'by a writer thinking nothing?' is the wordplay.
'INK' is hidden within the letters.
However, I'm unsure how this is indicated.
'used' acts as a link.
Can you help me to learn more?
(Other definitions for ink that I've seen before include "See 9" , "Liquid in pens" , "Fluid from squid" , "Writing fluid" , "Pen fluid" .)