Caught Alchemi cycling in compound? (8)
I believe the answer is:
chemical
'compound?' is the definition.
('chemical compound' can be a synonym of 'compound')
'caught alchemi cycling in' is the wordplay.
'caught' becomes 'c' (cricket abbreviation).
'cycling' is an anagram indicator.
'in' is an insertion indicator.
'alchemi' is an anagram of 'chemial'.
'c' put inside 'chemial' is 'CHEMICAL'.
(Other definitions for chemical that I've seen before include "Artificial compound" , "One may react" , "substance produced in a lab" , "Like 4 or 24 dn" , "Relating to compounds" .)