Shopping centre advertising in street outside - most people ignore it (5,5)
I believe the answer is:
small print
'most people ignore it' is the definition.
I can't tell whether this definition defines the answer.
'shopping centre advertising in street outside' is the wordplay.
'shopping centre' becomes 'mall' (a mall is a large shopping complex).
'advertising' becomes 'PR' (public relations).
'street' becomes 'st' (abbreviation).
'outside' is an insertion indicator (some letters go outside others).
'mall'+'pr'+'in'='mallprin'
'mallprin' going into 'st' is 'SMALL PRINT'.
Can you help me to learn more?
(Other definitions for small print that I've seen before include "Words often ignored" , "You may regret not reading this!" , "A trap for the unwary consumer" , "Inconspicuous part of agreement" , "Obscure terms" .)