For column, drop the conclusion, editor suggested (8)
I believe the answer is:
proposed
'suggested' is the definition.
('propose' can be a synonym of 'suggest')
'for column drop the conclusion editor' is the wordplay.
'for' becomes 'pro' (as in being 'pro' something).
'column' becomes 'post' (both can mean an upright support).
'drop the conclusion' means to remove the last letter.
'editor' becomes 'ed' (abbreviation).
'post' with its last letter removed is 'pos'.
'pro'+'pos'+'ed'='PROPOSED'
(Other definitions for proposed that I've seen before include "Asked to marry" , "Nominated, put forward for consideration" , "Offered for consideration - perhaps marriage" , "Moved" , "Intended (to do something)" .)