Noble, frightfully droll by end of party (6)
I believe the answer is:
lordly
'noble' is the definition.
('lordly' can be similar in meaning to 'noble')
'frightfully droll by end of party' is the wordplay.
'frightfully' indicates an anagram (I've seen this in other clues).
'by' is a charade indicator (letters next to each other).
'end of' suggests the final letters.
The last letter of 'party' is 'y'.
'droll' anagrammed gives 'lordl'.
'lordl'+'y'='LORDLY'
(Other definitions for lordly that I've seen before include "Noble, lavish" , "Majestic" , "Haughty, lofty" , "Haughty - arrogant" , "Imperious" .)