Outline of first dictionary by English writer (8)
I believe the answer is:
Here is my best explanation:
'outline' is the definition.
('describe' can be a synonym of 'outline')
'first dictionary by english writer' is the subsidiary indication.
'first' says to take the initial letters.
'by' says to put letters next to each other.
'english' becomes 'e' (abbreviation).
'writer' becomes 'scribe' (scribe is a kind of writer**).
The initial letter of 'dictionary' is 'd'.
'of' is the link.
(Other definitions for describe that I've seen before include "Draw (a geometrical figure)", "Tell what something is like", "style", "Give an account of extremely", "Report in detail", "Say what something is like (8)", "Portray in words", "provide an account", "Draw (figure); give account of" and "Give an account of in words".)