Write pigheaded letters! (3)
I believe the answer is:
pen
This might be a double definition.
'write' is the first definition.
(I know that write can be written as pen)
'pigheaded letters' is the second definition.
Although both the answer and definition are singular nouns, I don't see how they can define each other.
Can you help me to learn more?
(Other definitions for pen that I've seen before include "See 20" , "International writers's organisation" , "Write" , "'The ... is mightier than the sword'" , "Female swan" .)