Lines penned by directors offering a post (7)
I believe the answer is:
bollard
'a post' is the definition.
(bollard is a kind of post)
'lines penned by directors' is the wordplay.
'lines' becomes 'll' (I've seen this in other clues).
'penned by' indicates putting letters inside.
'directors' becomes 'board' (I've seen this before).
'll' inserted within 'board' is 'BOLLARD'.
'offering' is the link.
(Other definitions for bollard that I've seen before include "Roadside post" , "Thick post for mooring" , "Short post barring traffic" , "Post on road or quay" , "Strong post" .)