Writer absorbed by dictionary spread out (6)
I believe the answer is:
opened
'spread out' is the definition.
(I've seen this in another clue)
'writer absorbed by dictionary' is the wordplay.
'writer' becomes 'pen' (something which writes).
'absorbed by' indicates putting letters inside.
'dictionary' becomes 'OED' (Oxford English Dictionary).
'pen' placed into 'oed' is 'OPENED'.
(Other definitions for opened that I've seen before include "unwrapped" , "Turned the key, facilitated entry" , "Unlocked, made accessible" , "spoken out" , "Lifted the lid, say" .)