Old writers briefly endure dealing with technique (9)

I believe the answer is:

stylistic

'dealing with technique' is the definition.
(relating to style or technique)

'old writers briefly endure' is the wordplay.
'old writers' becomes 'styli' (I've seen this before).
'briefly' means to remove the last letter.
'endure' becomes 'stick' (I've seen this before).
'stick' with its final letter removed is 'stic'.
'styli'+'stic'='STYLISTIC'

(Another definition for stylistic that I've seen is " concerned with manners".)

I've seen this clue in The Times.

Want a hint initially instead of a full solution? Install my app