сам

мест.; ед. муж.

1-е лицо myself; 2-е лицо yourself; 3-е лицо himself

это говорит само за себя — it is self-explanatory, it speaks for itself

быть самим собой — be oneself

сам не свой — to be not himself, to be beside himself (with worry, grief, etc.)

сам себе хозяин — one's own master

сам собой — (случаться; происходить) (all) by itself, on its own, of itself, of its own accord/volition, automatically; (додуматься, добиться) (all) by oneself

самим собой — (быть, оставаться) to be oneself, to remain oneself, to be true to oneself, to remain true to oneself

само собой (разумеется) — it/that goes without saying, naturally, of course, needless to say, obviously, it/that stands to reason