Burglar vanishes, hiding grub (5)
I believe the answer is:
larva
'grub' is the definition.
(I know that grub can be written as larva)
'burglar vanishes hiding' is the wordplay.
'hiding' indicates the answer is hidden within the clue.
'LARVA' is hidden in the letters of 'burglar vanishes'.
(Other definitions for larva that I've seen before include "Caterpillar, for example" , "Wriggler" , "Immature stage of an insect" , "Animal in immature state" , "Early stage of creature" .)