I'd posted before on my reasons for abstaining from voting - I'm a conscientious non-voter. I'd not claimed priority in usage of the term, but I'd not known of any prior use. Turns out Joey King has used the term since at least 2004.
The arguments are different though. I'm a conscientious non-voter because of an odd contractarianism: if I vote, I agree with the rules of the game and consequently have given moral assent to the outcomes. And so I cannot vote without doing violence to myself. It's purely an inward-oriented argument. Voting is then closer to Sophie's Choice, but where your choosing one over the other only adds epsilon weight to which is chosen and non-voting only makes outcomes worse by epsilon. But if others who share my preferences also refuse to vote, I'm probably worse off.
Joey, in the link above, argues that mass conscientious non-voting could force social change. I'm less convinced of that argument - I'd rather expect that if all the libertarians failed to vote, democratic outcomes would be a bit worse as the location of the median voter would move maybe ten points closer to totalitarianism. And folks closer to the median won't abstain.