Polite of the General to rise in support of man (7)
I believe the answer is:
genteel
'polite' is the definition.
(synonyms)
'the general to rise in support of man' is the wordplay.
'the general' becomes 'lee' (Robert E. Lee - US revolutionary commander).
'to rise' is a reversal indicator.
'in support of' means one lot of letters go next to another (I've seen this in other clues).
'man' becomes 'gent' (gent is a kind of man).
'lee' written backwards gives 'eel'.
'eel' after 'gent' is 'GENTEEL'.
'of' is the link.
(Other definitions for genteel that I've seen before include "Terribly polite" , "Mannerly" , "Cultured; polite" , ""Refayned"" , "Affectedly refined and upper-crust" .)