Type of book work embraced by young boxer? (3-2)
I believe the answer is:
pop-up
'type of book' is the definition.
(I've seen this in another clue)
'work embraced by young boxer?' is the wordplay.
'work' becomes 'op' (abbreviation for opus).
'embraced by' indicates putting letters inside.
'young boxer?' becomes 'pup' (boxer is a type of dog).
'op' placed within 'pup' is 'POP-UP'.
(Other definitions for pop-up that I've seen before include "(Of a menu) visible when an option is chosen" , "Unrequested browser window" , "toddler's book?" , "Appear without warning" , "Appear (like toast?)" .)