One chapter in literature, OK? (5)
I believe the answer is:
licit
'ok?' is the definition.
(I've seen this before)
'one chapter in literature' is the wordplay.
'one chapter' becomes 'ci' (I can't justify this - if you can you should believe this answer much more).
'in' means one lot of letters goes inside another.
'literature' becomes 'lit' (abbreviation).
'ci' inserted into 'lit' is 'LICIT'.
Can you help me to learn more?
(Other definitions for licit that I've seen before include "Allowable" , "OK?" , "Legitimate" , "Within the law" , "Sanctioned" .)