Weeps about the mistaken conclusion of pretentious persons (5)
I believe the answer is:
snobs
'pretentious persons' is the definition.
(I've seen this before)
'weeps about the mistaken conclusion' is the wordplay.
'weeps' becomes 'sobs' (sobbing is a kind of weeping).
'about' means one lot of letters goes inside another.
'conclusion' suggests the final letters.
The last letter of 'mistaken' is 'n'.
'sobs' placed around 'n' is 'SNOBS'.
'of' is the link.
(Other definitions for snobs that I've seen before include "have jobs at last" , "Pretentious persons" .)