Suggest a work in poetic language (7)
I believe the answer is:
propose
'suggest' is the definition.
(as in proposing a plan)
'a work in poetic language' is the wordplay.
'a work' becomes 'op' (abbreviation for opus).
'in' means one lot of letters goes inside another.
'poetic language' becomes 'prose' (I have seen 'Ordinary language ' mean 'prose' so perhaps 'language' could also mean 'prose'. I am not sure about the 'poetic' bit.).
'op' going inside 'prose' is 'PROPOSE'.
Can you help me to learn more?
(Other definitions for propose that I've seen before include "Tender" , "Intend" , "Present for consideration" , "table" , "Suggest - make an offer" .)