Inscribe with acid (4)
I believe the answer is:
etch
'inscribe with acid' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for etch that I've seen before include "Draw on metal with acid" , "Delineate" , "Engrave metal plate using acid" , "Carve or engrave into surface" , "Carve (design) on a surface" .)