Composer typical of America (5)
I believe the answer is:
sousa
'composer' is the definition.
(I've seen this before)
'typical of america' is the wordplay.
'typical of' becomes 'so' (as in a statement like 'that's so you').
'america' becomes 'usa' (synonyms).
'so'+'usa'='SOUSA'
(Other definitions for sousa that I've seen before include "John Philip ---, US bandmaster" , "he produced the Washington Post" , "American composer known for marches" , "March man?" , "John Philip --, American march composer" .)