Pertinent article, two pages, on first site (8)
I believe the answer is:
apposite
'pertinent' is the definition.
(I know that pertinent can be written as apposite)
'article two pages on first site' is the wordplay.
'two pages' can mean two replacements for 'pages'.
'article' becomes 'a' (the indefinite article in English).
'pages' becomes 'p'.
'pages' becomes 'p'.
'on first' becomes 'o' (1st letter of 'on').
'a'+'p'+'p'+'o'+'site'='APPOSITE'
(Other definitions for apposite that I've seen before include "Suited for the purpose" , "Befitting" , "Meet" , "Appropriate, apt" , "Suitable, relevant" .)