A little taken aback by the information (4)
I believe the answer is:
data
'information' is the definition.
(data are bits of information)
'a little taken aback by' is the wordplay.
'little' becomes 'tad' (both can mean a small amount).
'taken aback' shows that the letters should be reversed in order.
'by' means one lot of letters go next to another.
'tad' backwards is 'dat'.
'a' after 'dat' is 'DATA'.
'the' acts as a link.
(Other definitions for data that I've seen before include "Raw facts" , "Pieces of information" , "Numerical facts" , "What's stored by computers" , "Facts and statistics collected together" .)