Article about another old clan chief (5)
I believe the answer is:
thane
'old clan chief' is the definition.
(historical title in Scotland)
'article about another' is the wordplay.
'article' becomes 'the' (the definite article).
'about' indicates putting letters inside.
'another' becomes 'an' (I can't explain this - if you can you should believe this answer much more).
'the' placed around 'an' is 'THANE'.
(Other definitions for thane that I've seen before include "Old lord" , "Title held by Macbeth" , "Medieval Scottish clan chief" , "Macbeth's Cawdor title" , "Anglo-Saxon aristocrat - old Scottish clan chief" .)