Hired vehicle carrying last of popular seafood (4)
I believe the answer is:
crab
'seafood' is the definition.
(crab is a kind of seafood)
'hired vehicle carrying last of popular' is the wordplay.
'hired vehicle' becomes 'cab' ().
'carrying' indicates putting letters inside.
'last of' says to take the final letters.
The last letter of 'popular' is 'r'.
'cab' going around 'r' is 'CRAB'.
(Other definitions for crab that I've seen before include "Seafood (that can be caught by a rower?)" , "Pincered crustacean" , "Stalk-eyed crustacean" , "One may be caught" , "move obliquely" .)