Got excited about American relish (5)
I believe the answer is:
gusto
'relish' is the definition.
(I know that relish can be written as gusto)
'got excited about american' is the wordplay.
'excited' indicates anagramming the letters.
'about' is an insertion indicator.
'american' becomes 'US' (United States).
'got' is an anagram of 'gto'.
'gto' enclosing 'us' is 'GUSTO'.
(Other definitions for gusto that I've seen before include "Great relish" , "Great enthusiasm" , "Zest, great enjoyment in doing" , "Spirit" , "Vigorous enthusiasm" .)