Necktie quickly sent back by Earl (5)
I believe the answer is:
noose
'necktie' is the definition.
'quickly sent back by earl' is the wordplay.
'quickly' becomes 'soon' (I've seen this in other clues).
'sent back' says the letters should be written backwards.
'by' says to put letters next to each other.
'earl' becomes 'e'.
'soon' in reverse letter order is 'noos'.
'noos'+'e'='NOOSE'
(Other definitions for noose that I've seen before include "Scaffold rope" , "Loop in rope that tightens when pulled" , "Hanging loop in rope" , "Ring of rope" , "Looped rope" .)