Chap left at a dead end (3)
I believe the answer is:
lad
'chap' is the definition.
(I know that chap can be written as lad)
'left at a dead end' is the wordplay.
'left' becomes 'l' (common abbreviation).
'at' says to put letters next to each other.
'end' suggests the final letters.
The last letter of 'dead' is 'd'.
'l'+'a'+'d'='LAD'
(Other definitions for lad that I've seen before include "Chap, fellow" , "Son" , "Stable employee" , "Boy, familiar" , "Young fellow" .)