A spoonerism of "smart fucker", a humorous and frequently derogatory term used to describe someone who demonstrates intelligence (or a reasonable facsimile) in a conversation. Can be applied to males or females. First heard in the early 1990s. Identical to fart smeller
In conversation, it is sometimes followed by the correct pronunciation for humorous effect.
Hey, you fixed that real quick-like! You must be a fart smucker!