Showing little humour, people often initially rejected weaker coffee
I believe the answer is:
po-faced
'showing little humour people often initially rejected weaker coffee' is the definition.
I can't judge whether this definition defines the answer.
'people often initially rejected weaker coffee' is the wordplay.
'initially' suggests taking the first letters.
'rejected' shows that the letters should be reversed in order.
'weaker coffee' becomes 'decaf' (I've seen this before. I am not sure about the 'weaker' bit.**).
The first letters of 'people often' is 'po'.
'decaf' written backwards gives 'faced'.
'po'+'faced'='PO-FACED'
Can you help me to learn more?
(Other definitions for po-faced that I've seen before include "With disapproving look" , "Informally solemn in appearance, like nocturnal vessel?" , "Humourless and disapproving" , "Not showing amusement, having solemn expression" , "Looking unamused" .)