They may be well held (4)
I believe the answer is:
inks
'they' is the definition.
Both the answer and definition are plural nouns.
Maybe you can see a link between them that I don't see?
I don't understand how the remainder of the clue works.
Can you help me to learn more?
(Other definitions for inks that I've seen before include "Liquids used for printing" , "Printers' mediums" , "Fluids from cuttlefish" , "Printing fluids" , "Sink beneath writing fluids" .)