saginjati

1. (saginjati se) to bend down; to stoop
   Bole me leđa kad se saginjem. — My back hurts when I bend down.
   Stalno se saginjao da pokupi igračke. — He kept bending down to pick up the toys.
2. (+ acc., often the head) to bend; to bow
   Deca su saginjala glave nad sveskama. — The children were bowing their heads over their notebooks.
3. (saginjati glavu pred someone) to bow down; to submit
   Nikada nije saginjao glavu pred šefom. — He never bowed down to his boss.

Most often used with se meaning "to bend down"; the perfective is sagnuti.