I believe it's slue-foot, not slew-foot, but I could be wrong.

I am conscious of the fact that there is really no "right" or "wrong" in spelling - only usage. But on this side of the pond, I have only come across "slew-footed" (and it isn't a common saying here, anyway.) "Slew" is used to mean, "at an angle to the true direction" - e.g., the car was slewed across the road after it skidded.

"Slewed" is also a slang term for drunk.
(This is quite apart from its meaning as the past of "slay", of course.)