Large rodent (3)
(Other definitions for rat that I've seen before include "Inform" , "one who betrayed" , "one escaping doomed vessel?" , "Rodent pest" , "shopper" .)
'large rodent' is the definition.
(I've seen this before)
This is the entire clue.
(Other definitions for capybara that I've seen before include "Largest rodent" , "largest animal of its kind" , "Pay a crab (anag) - rodent" , "Large South American rodent" .)
'large rodent' is the definition.
(I've seen this before)
This is all the clue.
(Other definitions for agouti that I've seen before include "Guinea pig-like rodent" , "S.Amer. rodent" , "S. American burrowing rodent" , "South American rodent" , "Rabbit-sized rodent of South America valued as food" .)