This is the 398th most frequent Russian word.
самого
"Самого" is the genitive or accusative form of "самый," meaning "of the most," "the very," or "of oneself" depending on context.
The word 'самого' here intensifies the direct object 'его', emphasizing that the person referred to is the exact individual seen.
Я видел его самого.
I saw him himself.
Here, 'самого' refers to 'слова' and is used to emphasize that the discussion is focusing on the word itself, not what it represents.
Мы говорим о значении самого слова.
We are talking about the meaning of the word itself.
In this case, 'самого' serves as a possessive adjective, emphasizing the superlative quality of 'высокого уровня' (highest level).