A bible in US city for bookworm, perhaps (5)
I believe the answer is:
larva
'bookworm perhaps' is the definition.
(larva is a young insect eg a young bookworm)
'a bible in us city' is the wordplay.
'bible' becomes 'rv' (Revised Version, revision of King James Bible).
'in' indicates putting letters inside.
'us city' becomes 'la'.
'a'+'rv'='arv'
'arv' placed inside 'la' is 'LARVA'.
'for' acts as a link.
(Other definitions for larva that I've seen before include "Immature form of an insect before metamorphosis" , "Insect's feeding stage" , "Caterpillar perhaps" , "Grub, caterpillar stage" , "early form" .)