Majestic and terribly large (5)
I believe the answer is:
regal
'majestic' is the definition.
(I know that majestic can be written as regal)
'terribly large' is the wordplay.
'terribly' indicates an anagram.
'large' is an anagram of 'REGAL'.
'and' acts as a link.
(Other definitions for regal that I've seen before include "Fit for a monarch" , "King-like" , "Royal - lager (anag)" , "Befitting a monarch" , "Magnificent, dignified" .)