Tailed off in particular (6)
I believe the answer is:
detail
'particular' is the definition.
(I know that particular can be written as detail)
'tailed off' is the wordplay.
'off' indicates anagramming the letters.
'tailed' with letters rearranged gives 'DETAIL'.
'in' acts as a link.
(Other definitions for detail that I've seen before include "A small part of something" , "Unimportant area" , "A piece of information, may be minor" , "Individual fact or feature, may be unimportant" , "Small section of a work of art" .)