Book pilgrimage, to return before motorway opens (8)
I believe the answer is:
jeremiah
'book' is the definition.
(I know that Jeremiah is a book)
'pilgrimage to return before motorway opens' is the wordplay.
'pilgrimage' becomes 'haj' (haj is a kind of pilgrimage).
'to return' shows that the letters should be reversed in order.
'before' becomes 'ere' (poetic term for 'before').
'motorway' becomes 'MI' (resembles Me, English motorway).
'opens' is an insertion indicator (some letters open a gap in others).
'haj' reversed gives 'jah'.
'ere'+'mi'='eremi'
'jah' placed around 'eremi' is 'JEREMIAH'.
(Other definitions for jeremiah that I've seen before include "Continuous complainer" , "OT character" , "book" , "Continual complainer" , "Gloomy prophet" .)