1.c. 神話 (shinwa: god + talk) means “myth.”
2.b. 死神 (shinigami: death + god) means “Grim Reaper.”
3.a and d. 神経 (shinkei: soul, mind, gods ＋ to pass through) means both “nerve (anatomical)” and “sensitivity.”
4.a. 異教 (ikyō: different + religion) means “paganism.”
You may know 教 as oshi(eru), “to teach.” It also means “religion,” as in 教会 (kyōkai: church), 宗教 (shūkyō: religion), and 仏教 (bukkyō: Buddhism).
5.b and c. 再現 (saigen: again + existing) means both “repetition” and “reappearance.”
6.d. 滞在 (taizai: to stagnate + to exist) means “to stay.”
It might sound as if to stagnate + to exist would be a lofty combination, reserved for deep, metaphysical discussions. But in fact, 滞在 is a mundane, everyday word, as these sentences show:
滞在の目的は何ですか。
Taizai no mokuteki wa nan desu ka.
What’s the purpose of your visit?目的 (mokuteki: purpose) aim + target
何 (nan: what)３ヵ月滞在します。
Sankagetsu taizai shimasu.
I’ll be staying here for three months.-ヵ月 (-kagetsu: counter for the number of months)
いつまで日本に滞在のご予定ですか。
Itsu made Nihon ni taizai no go-yotei desu ka.
How long are you staying in Japan?日本 (Nihon: Japan) Japan + origin
予定 (yotei: plan)
in advance + to determine
