Detective reveals earl's lost article in jar (8)
I believe the answer is:
sherlock
'detective' is the definition.
(I know that sherlock is a type of detective)
'earl's lost article in jar' is the wordplay.
'lost' is a deletion indicator.
'article' becomes 'a' (English indefinite article).
'in' means one lot of letters goes inside another.
'jar' becomes 'shock' (I've seen this before).
'earl' with 'a' taken out is 'erl'.
'erl' inserted within 'shock' is 'SHERLOCK'.
'reveals' is the link.
(Other definitions for sherlock that I've seen before include "Fictional detective" , "Arthur Conan Doyle's detective" , "Conan Doyle's sleuth, . . . . . . . . Holmes" , "Fictional sleuth . . . . . . . . Holmes" , "Mr Holmes" .)