Dear old writers this writer's pursuing (9)
I believe the answer is:
expensive
'dear' is the definition.
(similar in meaning)
'old writers this writer's pursuing' is the wordplay.
'old' becomes 'ex' (prefix meaning former or onetime).
'writers' becomes 'pens' (writing implements).
'this writer's' becomes 'ive' ('I have' can refer to the person writing).
'pursuing' means one lot of letters go next to another.
'ex'+'pens'+'ive'='EXPENSIVE'
(Other definitions for expensive that I've seen before include "Very costly or dear" , "Pricey" , "High in price" , "Costing a lot of money" , "not going for a song" .)