Sort of oil Titian turned against (4)

I believe the answer is:
derv
'sort of oil' is the definition.
The answer and definition can be both substances as well as being singular nouns.
Maybe they are linked in a way I don't understand?
'titian turned against' is the wordplay.
'titian' becomes 'red' (Titian can mean a red colour).
'turned' is a reversal indicator.
'against' becomes 'v' (abbreviation for 'versus').
'red' written backwards gives 'der'.
'der'+'v'='DERV'
Can you help me to learn more?
(Other definitions for derv that I've seen before include "Vehicle fuel oil" , "Diesel engine fuel oil" , "Type of fuel" , "Lorry fuel" , "Water monster" .)
