Bookish drunk, discontented revolutionary concealing age (8)
I believe the answer is:
literary
'bookish' is the definition.
(I've seen this before)
'drunk discontented revolutionary concealing age' is the wordplay.
'drunk' becomes 'lit' (I've seen this in another clue).
'discontented' means to remove the middle letters (the word's contents are removed).
'concealing' means one lot of letters goes inside another.
'age' becomes 'era' (both can mean a long time).
'revolutionary' with its centre taken out is 'ry'.
'lit'+'ry'='litry'
'litry' going around 'era' is 'LITERARY'.
(Other definitions for literary that I've seen before include "Concerning books" , "Bookish" , "well read" , "Of or concerned with good books and writing" , "Learned" .)