Look in Iron City for serious American crime (6)
I believe the answer is:
felony
'serious american crime' is the definition.
'felony' can be an answer for 'crime' (felony is a kind of crime). I am not certain of the 'serious american' bit.
'look in iron city' is the wordplay.
'look' becomes 'lo' (archaic term meaning 'look!').
'in' is an insertion indicator.
'iron' becomes 'Fe' (Fe is the chemical symbol for iron).
'city' becomes 'ny' (short for New York).
'fe'+'ny'='feny'
'lo' inserted into 'feny' is 'FELONY'.
'for' is the link.
Can you help me to learn more?
(Other definitions for felony that I've seen before include "Criminal act" , "Grave crime" , "Criminal offence" , "Serious crime" .)