Metalworker (5)
(Other definitions for robot that I've seen before include "Android, possibly" , "Automation" , "Programmable machine" , "programmed servant" , "Automatic machine" .)
'metalworker' is the definition.
(synonyms)
This is the entire clue.
(Other definitions for smith that I've seen before include "Black . . . . . or gun . . . . ." , "Worker in forge" , "Common family name" , "Person who makes things in metal, may be black" , "Metal-worker" .)
'metalworker' is the definition.
(I've seen this before)
This is all the clue.
(Other definitions for welder that I've seen before include "Metal joiner" , "metalworker" , "One joining" , "Torch-bearer" , "Skilled worker who fuses metals using heat" .)