Fashionable resident getting old - very original (10)
I believe the answer is:
innovative
'original' is the definition.
(similar in meaning)
'fashionable resident getting old very' is the wordplay.
'fashionable' becomes 'in' (in can mean fashionable or trendy).
'resident' becomes 'native' (I've seen this in other clues).
'getting' means one lot of letters goes inside another.
'old very' becomes 'ov' (this might be a standard abbreviation which I don't know about).
'native' going around 'ov' is 'novative'.
'in'+'novative'='INNOVATIVE'
Can you help me to learn more?
(Another definition for innovative that I've seen is " Using new methods".)