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' (U.S. is an example) and 'us' is located in the answer.
'president' could be 'abe' (Abraham (Abe) Lincoln) and 'abe' is found in the remaining letters.
No letters remain.
This explanation may well be incorrect...
'with' is the 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" .)