Inexperienced regarding blocking information (5)
I believe the answer is:
green
'inexperienced' is the definition.
('green' can be similar in meaning to 'inexperienced')
'regarding blocking information' is the wordplay.
'regarding' becomes 're'.
'blocking' means one lot of letters goes inside another.
'information' becomes 'gen' (gen is a kind of information**).
're' inserted within 'gen' is 'GREEN'.
(Other definitions for green that I've seen before include "Area around a golf hole" , "Colour of malachite" , "Environmentally concerned" , "Ecologically correct" , "Naive; colour" .)