President entertaining his country with insulting language (5)
I believe the answer is:
abuse
'insulting language' is the definition.
(I've seen this in another clue)
'president entertaining his country' is the wordplay.
I cannot really see how this works, but
'country' could be 'us' (United States) and 'us' is found in the answer.
'president' could be 'abe' (Abraham (Abe) Lincoln) and 'abe' is found in the remaining letters.
This accounts for all the letters.
This may be the basis of the clue (or it may be nonsense).
'with' acts as a link.
Can you help me to learn more?
(Other definitions for abuse that I've seen before include "Cruel treatment" , "vilification" , "Subject to verbal assault and insults" , "Treat badly - hurl insults" , "Misemploy - invective" .)