Gastroenterologist finally writes about American's terrible wind (7)
I believe the answer is:
twister
'wind' is the definition.
(I've seen this before)
'gastroenterologist finally writes about' is the wordplay.
'finally' suggests the final letters.
'about' indicates anagramming the letters.
The final letter of 'gastroenterologist' is 't'.
'writes' with letters rearranged gives 'wister'.
't'+'wister'='TWISTER'
'american's terrible' acts as a link.
I am not very happy about this link. Some or all of it may be part of another bit of the clue.
Can you help me to learn more?
(Other definitions for twister that I've seen before include "Rogue - tornado" , "Cheat - tornado" , "conman" , "'sixties dancer?" , "Con artist - tornado" .)