задвинуться (Russian) comes from Russian задви́нуть, from Russian дви́нуть, from Proto-Slavic dvignǫti, from Proto-Slavic dvigati, from Proto-Slavic d(ъ)vigъ, from Proto-Slavic d(ъ)va — 2.
задвинуться (Russian): to shut, to close, to slide; passive of...