Can run inside to get American grub (5)
I believe the answer is:
larva
'grub' is the definition.
(thesaurus)
'can run inside to get american' is the wordplay.
I cannot really understand how this works, but
'run' could be 'r' (cricket abbreviation) and 'r' is found within the answer.
'can' could be 'lav' ('lav' can be a synonym of 'can') and 'lav' is found in the leftover letters.
'american' could be 'a' (common abbreviation - e.g. in organisation names) and 'a' is present in the answer.
No letters remain.
This explanation may well be incorrect...
Can you help me to learn more?
(Other definitions for larva that I've seen before include "shows form of immaturity" , "nit?" , "Immature stage of an insect" , "Juvenile form of insect" , "Immature form of an insect before metamorphosis" .)