きけん棄権kiken
1.

The act of choosing not to exercise one's right, such as refraining from casting a vote or participating in a decision-making process.

2.

The deliberate decision to forgo participation in an event or competition, thereby relinquishing the opportunity to take part.

3.

A formal renunciation of one's rights or entitlements, resulting in no involvement in an election or a contest.

Example:

いざ投票という時、彼は棄権した。

きけんしゃ棄権者kikensha
1.

An individual who chooses not to participate in an election or vote, often abstaining for personal or political reasons.

2.

A person who has the eligibility to vote but decides not to cast their ballot during an election, reflecting disinterest or discontent with the available options.

3.

Someone who refrains from making their choice known in an electoral process, thereby contributing to the overall phenomenon of voter apathy.