Vegetable combined in side, lacking marrow? (5)
I believe the answer is:
swede
'vegetable' is the definition.
(I know that swede is a type of turnip)
'combined in side lacking marrow?' is the wordplay.
'combined' becomes 'wed' (I've seen this in another clue).
'in' is an insertion indicator.
'side lacking marrow?' becomes 'se' (I am not sure about this - if you are sure you should give a lot more credence to this answer).
'wed' going within 'se' is 'SWEDE'.
Can you help me to learn more?
(Other definitions for swede that I've seen before include "Large root vegetable" , "Nobel for one" , "Person like Strindberg" , "in Northern Europe" , "N European" .)