Most unhappy to learn the store has gone into liquidation (9)
I believe the answer is:
heartsore
'store has gone into liquidation' is the definition.
I can't judge whether this definition defines the answer.
'most unhappy to learn the' is the wordplay.
'most unhappy' becomes 'sore' (I am not sure about the 'most' bit.).
'to' says to put letters next to each other (I've seen this in other clues).
'learn' becomes 'hear' (synonyms).
'the' becomes 't' (the is pronounced as a 't' sound in some dialects).
'hear'+'t'='heart'
'sore' after 'heart' is 'HEARTSORE'.
Can you help me to learn more?
(Other definitions for heartsore that I've seen before include "Blue" , "Sad in cardiac way - suffering from angina?" .)