All the day before Rosemary extremely on edge (5,4)
I believe the answer is:
every inch
'all' is the definition.
Both the answer and definition are adverbs. Maybe they are linked in a way I don't understand?
'day before rosemary extremely on edge' is the wordplay.
'day before' becomes 'eve' (the eve of something is the night before).
'extremely' suggests removing the centre (only the extremes of the word are used).
'on' says to put letters next to each other (in a down clue, letters appear on others).
'edge' becomes 'inch' (as in edging or inching along).
'rosemary' with its middle removed is 'ry'.
'eve'+'ry'+'inch'='EVERY INCH'
'the' acts as a link.
Can you help me to learn more?
(Other definitions for every inch that I've seen before include "Thoroughly" , "completely" , "Absolutely!" , "Wholly" , "Entirely" .)
