Musical craft (4,4)
'musical' is the definition.
(musical by Jerome Kern)
'craft' is the wordplay.
I cannot quite understand how this works, but
'craft' could be 'boat' (boat is a kind of craft) and 'boat' is found in the answer.
The remaining letters 'show' is a valid word which might be clued in a way I don't understand.
This explanation may well be incorrect...
Can you help me to learn more?
This clue is a double definition.
'musical' is the first definition.
(I've seen this before)
'craft' is the second definition.
(showboat is a kind of craft)
(Other definitions for showboat that I've seen before include "stage work for American theatre" , "parade" , "Floating theatre - musical" , "Floating entertainment" , "Kern Mississippi musical" .)