Human machine caught by returning or going, initially (6)
I believe the answer is:
cyborg
'human machine' is the definition.
I know nothing about this answer so I cannot tell whether this works.
'caught by returning or going initially' is the wordplay.
'caught' becomes 'c' (cricket abbreviation).
'returning' says the letters should be written in reverse.
'initially' indicates taking the first letters.
The initial letter of 'going' is 'g'.
'by' in reverse letter order is 'yb'.
'c'+'yb'+'or'+'g'='CYBORG'
Can you help me to learn more?
(Other definitions for cyborg that I've seen before include "Human whose body has been taken over by manmade devices" , "Robot made of biological and machine parts" , "Science-fiction human with artificial body parts" , "Human whose body has been taken over by machines" , "Bionic man (or woman)" .)