Tense son, having caught flipping chopper, is a state (5)
I believe the answer is:
texas
'state' is the definition.
(I know that Texas is American state)
'tense son having caught flipping chopper' is the wordplay.
'tense' becomes 't' (grammatical abbreviation).
'son' becomes 's' (genealogical abbreviation for son).
'having caught' means one lot of letters goes inside another.
'flipping' says the letters should be written in reverse.
'chopper' becomes 'axe' (something which chops).
'axe' reversed gives 'exa'.
't'+'s'='ts'
'ts' placed around 'exa' is 'TEXAS'.
'is a' is the link.
(Other definitions for texas that I've seen before include "Second-largest US state by area" , "Large US state" , "State on the Gulf of Mexico" , "America's Lone Star State" , "11's favourite baseball team" .)