Duke in hurry meets new set (6)
I believe the answer is:
harden
'set' is the definition.
(I've seen this in another clue)
'duke in hurry meets new' is the wordplay.
'duke' becomes 'd' (abbreviation).
'in' means one lot of letters goes inside another.
'hurry' becomes 'hare' (I've seen this in other clues).
'meets' says to put letters next to each other.
'new' becomes 'n' (common abbreviation eg NT for New Testament).
'd' going inside 'hare' is 'harde'.
'harde'+'n'='HARDEN'
(Other definitions for harden that I've seen before include "Become less soft" , "Become less sympathetic" , "Temper, steel say" , "Set; become tougher" , "Small fly" .)