Lobster relative (4)
I believe the answer is:
crab
'lobster relative' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Other definitions for crab that I've seen before include "Seashore creature" , "move obliquely" , "One may be caught" , "A crustacean; type of apple" , "One fired from gun" .)