One who works like a horse? (6)
I believe the answer is:
trojan
'one who works' is the definition.
The answer is a person as well as being a singular noun. This is suggested by the definition.
'a horse?' is the wordplay.
I cannot quite understand how this works, but
'a' could be 'an' and 'an' is present in the answer.
This explanation may well be incorrect...
'like' acts as a link.
Can you help me to learn more?
(Other definitions for trojan that I've seen before include "Native of Troy" , "Native like Helen" , "Of Troy or its people" , "one typically hard-working" , "Hard grafter (from an ancient city?)" .)