Exclusive landed in middle of week (5)
I believe the answer is:
elite
'exclusive' is the definition.
(I've seen this before)
'landed in middle of week' is the wordplay.
'landed' becomes 'lit' (I've seen this in another clue).
'in' is an insertion indicator.
'middle of' indicates the central letters.
The centre of 'week' is 'ee'.
'lit' inserted within 'ee' is 'ELITE'.
(Other definitions for elite that I've seen before include "Cream, the pick" , "Superior or favoured group of people" , "A privileged or superior social group" , "Chosen ones" , "Pick of the bunch" .)