Enthusiasm after good stink from ancient incendiary weapon (5,4)
I believe the answer is:
greek fire
'ancient incendiary weapon' is the definition.
'Greek fire' can be an answer for 'weapon' (Greek fire is an example). I'm unsure of the 'ancient incendiary' bit.
'enthusiasm after good stink' is the wordplay.
'enthusiasm' becomes 'fire' (I've seen this in another clue).
'after' means one lot of letters go next to another.
'good' becomes 'g' (abbreviation).
'stink' becomes 'reek' (synonyms).
'g'+'reek'='greek'
'fire' after 'greek' is 'GREEK FIRE'.
'from' acts as a link.
Can you help me to learn more?
(Another definition for greek fire that I've seen is " Burning compound used to burn ships (hist.)".)