Wearing such an expression, Enid was upset by dad (6)
I believe the answer is:
pained
'wearing such an expression' is the definition.
Both the definition and answer are adjectives. Maybe there's a link between them I don't understand?
'enid was upset by dad' is the wordplay.
'was upset' indicates an anagram (I've seen 'are upset' mean this).
'by' means one lot of letters go next to another.
'dad' becomes 'pa' (both can mean one's father).
'enid' with letters rearranged gives 'ined'.
'ined' put after 'pa' is 'PAINED'.
Can you help me to learn more?
(Other definitions for pained that I've seen before include "Hurt and disapproving (6)" , "Distressed or hurt in feelings" , "Caused suffering to" , "Distressed so it hurts?" , "Caused hurt." .)