A charming companion with wit (5)
I believe the answer is:
witch
'a charming' is the definition.
I can't tell whether this definition defines the answer.
'companion with wit' is the wordplay.
'companion' becomes 'ch' (Companion of Honour).
'with' is a charade indicator (letters next to each other).
'ch' put after 'wit' is 'WITCH'.
Can you help me to learn more?
(Other definitions for witch that I've seen before include "One supposed to have magical powers" , "Black cat and broomstick owner?" , "Female practising black magic" , "Female sorcerer" , "... and magician" .)