Take drugs one's discovered in book (3-3)
I believe the answer is:
dog-ear
'in book' is the definition.
The answer and definition can be both related to communication as well as being singular nouns.
Perhaps there's an association between them I don't understand?
'take drugs one's' is the wordplay.
I cannot really see how this works, but
'take' could be 'do' (eg taking or doing drugs) and 'do' is found within the answer.
'drugs' could be 'gear' (gear can informally mean illegal drugs) and 'gear' is found in the answer.
No letters remain.
This explanation may well be incorrect...
'discovered' is the link.
Can you help me to learn more?
(Other definitions for dog-ear that I've seen before include "Turned-over page corner" , "Fold on page's corner" , "Crease in book page like canine appendage" , "Hint of shabbiness" , "Corner of a page turned down to mark your place" .)