Lofty duke following senior relative (5)
I believe the answer is:
grand
'lofty' is the definition.
(thesaurus)
'duke following senior relative' is the wordplay.
'duke' becomes 'd'.
'following' says to put letters next to each other.
'senior relative' becomes 'gran' (I've seen this in other clues**).
'd' after 'gran' is 'GRAND'.
(Other definitions for grand that I've seen before include "Majestic" , "Designed to impress" , "Impressive, large" , "1,000 GBP" , "Splendid - piano" .)