They may have to be driven home (5)
I believe the answer is:
nails
'they' is the definition.
Both the definition and answer are plural nouns.
Maybe there's an association between them I don't understand?
I don't understand how the remainder of the clue works.
Can you help me to learn more?
(Other definitions for nails that I've seen before include "Fastens with spikes" , "Metal fasteners" , "Cock's crest" , "Fixing spikes" , "Slain with metal pins" .)