Returned soldier in it, doctor? Active beginning combustion? (8)
I believe the answer is:
ignition
'beginning combustion?' is the definition.
'ignition' can be an answer for 'combustion?' (ignition is a kind of combustion). I'm unsure of the 'beginning' bit.
'returned soldier in it doctor? active' is the wordplay.
'returned' is a reversal indicator.
'soldier' becomes 'GI' (GI can mean a US soldier).
'doctor?' indicates an anagram (I've seen 'doctor' mean this).
'active' becomes 'on' (I've seen this in other clues).
'gi' written backwards gives 'ig'.
'in'+'it'='init'
'init' with letters rearranged gives 'niti'.
'ig'+'niti'+'on'='IGNITION'
Can you help me to learn more?
(Other definitions for ignition that I've seen before include "Starting of combustion" , "Internal-combustion engine's firing system" , "Act of lighting burner" , "Car engine starter" , "Mechanism to start car engine by sparking fuel" .)