Type in information, extremely reliable (5)
I believe the answer is:
genre
'type' is the definition.
(I've seen this before)
'information extremely reliable' is the wordplay.
'information' becomes 'gen' (gen is a kind of information**).
'extremely' means to remove the middle letters.
'reliable' with its centre taken out is 're'.
'gen'+'re'='GENRE'
'in' acts as a link.
(Other definitions for genre that I've seen before include "Kind" , "Style (of art/literature)" , "Style of work" , "Writing style" , "Brand" .)