Not impressed (9)
'not impressed' is the definition.
The answer and definition are not the same part of speech. However, past participle verbs and adjectives can occasionally mean the same thing.
'not impressed' is the wordplay.
'not' becomes 'un' (prefix meaning 'not').
'impressed' becomes 'printed' ('print' can be a synonym of 'impress').
'un'+'printed'='UNPRINTED'
Can you help me to learn more?
'not impressed' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Other definitions for meh that I've seen before include "Not much cop" , "Unexciting (modern slang)" , "Who cares" , "expression of indifference" , "am I bovvered?" .)