Disapproving of Post Office circulating weak coffee (2-5)
I believe the answer is:
po-faced
'disapproving' is the definition.
(I've seen this before)
'post office circulating weak coffee' is the wordplay.
'post office' becomes 'po' (abbreviation).
'circulating' says the letters should be written in reverse.
'weak coffee' becomes 'decaf' (type of coffee. I am not sure about the 'weak' bit.).
'decaf' backwards is 'faced'.
'po'+'faced'='PO-FACED'
'of' acts as a link.
Can you help me to learn more?
(Other definitions for po-faced that I've seen before include "Humourlessly disapproving" , "Not showing amusement, having solemn expression" , "Informally solemn in appearance, like nocturnal vessel?" , "Looking unamused" , "Wearing a stern expression" .)