Whopping (5)
'whopping' is the definition.
(similar in meaning)
This is the entire clue.
(Other definitions for large that I've seen before include "Big - 5 down (anag)" , "Of considerable size or extent" , "At which criminals possibly are free" , "jumbo" , "Strapping" .)
(Other definitions for great that I've seen before include "Very large in size, quantity, etc." , "Large, fantastic" , "Waterbird" , "Marvellous; big" , "Terrific" .)
(Other definitions for strapping that I've seen before include "Big" , "Robust" , "stalwart" , "Brawny" , "Tying up" .)
(Other definitions for titanic that I've seen before include "made of metal" , "In attic (anag.)" , "Doomed liner found in attic" , "Exceptionally powerful" , "Of enormous size, like the stricken liner" .)
(Other definitions for outsize that I've seen before include "Overlarge" , "big girl's blouse, for example?" , "Exceptionally large" , "Massive" , "Extra-large (garment)" .)