A friendly card from the palace (3)
I believe the answer is:
pal
'a friendly' is the definition.
I can't tell whether this definition defines the answer.
'card from the palace' is the wordplay.
'card' becomes 'ace' (ace is a type of playing card).
'from' is a deletion indicator.
'palace' with 'ace' taken away is 'PAL'.
Can you help me to learn more?
(Other definitions for pal that I've seen before include "Crony" , "Mate, buddy" , "Bud" , "Friend (colloq.)" , "Close friend" .)