It seems like maybe cancelled downvote might be less...weird?
It's not really wrong, but I agree it's a bit weird.
It's even longer so it may not be practical, but I opt for
downvote removed upvote removed
dv removed uv removed
or as suggested by MDMarra
↓ removed ↑ removed
or as suggested by slhck, even more in keeping with SO's general design
▼ removed ▲ removed
to keep it both simple and within the space limits?
I'm not a fan of the word "cast", so I recommend the following for when you vote up or down on a question:
If you want to replace that with iconography, that works too, but the above is pretty simple (even simpler than upvote/downvote, IMO) and should be understood by anyone looking at it.
However, I don't see the reason to use "removed", since the common terminology when it comes to votes is rescind.
So I'd like to just see "rescind". I don't need to see "upvote/downvote".
IMO, "upvote"/"downvote" is an over-specialization of the voting action. You simply cast a vote up or down, and conversely the action you perform is "rescind", the direction doesn't matter since its reflected in the rep.
You can even take it one step further and say that you can just have "Voted" when a user casts a vote, and let the rep reflect the direction the vote was cast.
If you want to be really consistent you can simply have:
Which ultimately, I like the best, as it reduces four states down to two while being consistent.
How about "withdrawn"? It sounds more of an active verb to me. Or would that be ambiguous as well?
cancelled downvote undownvote
Granted, "undownvote" isn't a real word, but expanding it fully would amount to making the vote-type column much wider than it needs to be. "undownvote" keeps it still roughly in the same realm as when there are just normal votes.
The word undownvote implies that unupvote exists too.
I presume that is to differentiate it from reversal, which is what the system or devs do if you have serial voting occur. But the question: Why are my downvotes being undownvoted? says that the system uses that word too.
Perhaps "reversed" would be appropriate if the system or a moderator reversed the decision and "reversal" ( or 180°, if eyesight/accessability is a concern) if the person changed their mind after five minutes. Made up words are probably challenging for some whom English is not their first language and they might feel excluded, not understanding the concept.