Give instruction to companion after a meal (5)
I believe the answer is:
teach
'give instruction to' is the definition.
(I've seen this before)
'companion after a meal' is the wordplay.
'companion' becomes 'ch' (I've seen this in other clues).
'after' says to put letters next to each other.
'a meal' becomes 'tea' (tea is a kind of meal).
'ch' after 'tea' is 'TEACH'.
(Other definitions for teach that I've seen before include "Work in school" , "Blackbeard" , "Convey knowledge to students" , "Pass on knowledge" , "Impart knowledge" .)