One completely lacking in IT experience (6)
I believe the answer is:
virgin
'it experience' is the definition.
The definition suggests a singular noun which matches the answer.
'one completely lacking in' is the wordplay.
I cannot really see how this works, but
'one' could be 'i' (Roman numeral) and 'i' is found within the answer.
'in' is within the answer.
This may be the basis of the clue (or it may be nonsense).
Can you help me to learn more?
(Other definitions for virgin that I've seen before include "New" , "Pure" , "Unsullied" , "Unspoilt" , "Chaste" .)