With a sharp point I am able to provide some defence (8)
I believe the answer is:
barbican
'some defence' is the definition.
(I've seen this before)
'with a sharp point i am able' is the wordplay.
'with' says to put letters next to each other.
'a sharp point' becomes 'barb' (I've seen this in another clue).
'i am able' becomes 'I can' (I can).
'barb'+'ican' is 'BARBICAN'.
'to provide' acts as a link.
(Other definitions for barbican that I've seen before include "Walled outwork at the entrance to a fortification" , "Defensive tower over gateway" , "Watchtower over a castle gate - bin a crab (anag)" , "Watchtower - City of London building complex" , "London buildings with Arts Centre" .)