US President has the last word when entertaining the French sailors (4,6)
I believe the answer is:
able seamen
'sailors' is the definition.
(able seaman is a kind of sailor)
'us president has the last word when entertaining the french' is the wordplay.
'us president' becomes 'Abe' (Abraham (Abe) Lincoln).
'has' means one lot of letters go next to another.
'the last word' becomes 'amen' (last word in a prayer).
'when entertaining' indicates putting letters inside.
'the french' becomes 'les' (plural form of 'the' in French).
'abe'+'amen'='abeamen'
'abeamen' enclosing 'les' is 'ABLE SEAMEN'.
(Other definitions for able seamen that I've seen before include "ratings" , "sailors" .)