In addressing a 'Mr', it's a bit picturesque and old-fashioned (3)
I believe the answer is:
esq
'old-fashioned' is the definition.
Although both the answer and definition are singular nouns, I don't see how they can define each other.
'in addressing a mr it's a bit picturesque' is the wordplay.
'ESQ' is hidden in amongst the letters.
However, I am not sure how the hidden word is indicated.
'and' acts as a link.
Can you help me to learn more?
(Other definitions for esq that I've seen before include "Old title of respect after the name" , "In brief, courtesy suffix after man's name" , "Short courtesy title placed after man's name" , "Gentleman's title (abbrev.)" , "In brief, courtesy title after man's surname" .)