Require lead, shortened by half, for pointer (6)
I believe the answer is:
needle
'pointer' is the definition.
(I know that needle is a type of pointer)
'require lead shortened by half' is the wordplay.
'require' becomes 'need' (synonyms).
'lead' is a charade indicator (letters next to each other).
'shortened by half' becomes 'le' (I can't justify this - if you can you should give a lot more credence to this answer).
'need'+'le'='NEEDLE'
'for' acts as a link.
Can you help me to learn more?
(Other definitions for needle that I've seen before include "Informal name for hypodermic syringe" , "Knitting rod" , "Pin" , "Goad, provoke" , "See 6" .)