Information on jacket smear, black (5)
I believe the answer is:
blurb
'information on jacket' is the definition.
The answer and definition can be both related to communication as well as being singular nouns.
Perhaps you can see an association between them that I can't see?
'smear black' is the wordplay.
'smear' becomes 'blur' (synonyms).
'black' becomes 'b' (as in pencil classifications).
'blur'+'b'='BLURB'
Can you help me to learn more?
(Other definitions for blurb that I've seen before include "Book endorsement" , "stuff on jacket" , "Publisher's descrtion of book" , "printed on jacket" , "Commendations on book jacket" .)