Column is penned by debauched bloke (7)
I believe the answer is:
obelisk
'column' is the definition.
(I know that obelisk is a type of column)
'is penned by debauched bloke' is the wordplay.
'penned by' indicates putting letters inside (inserted letters are penned in).
'debauched' indicates an anagram.
'bloke' with letters rearranged gives 'obelk'.
'is' going within 'obelk' is 'OBELISK'.
(Other definitions for obelisk that I've seen before include "Tapering square pillar" , "Stone pillar tapering towards a point" , "Eg Cleopatra's Needle" , "Square stone column that tapers" , "Monument with four sides and tapering top" .)