This is the 992nd most frequent Croatian word.
glavom
"Glavom" means "with the head" in English.
Here, "glavom" is used metaphorically to represent logical reasoning or thinking.
Razmišljao je glavom, a ne srcem.
He was thinking with his head, not his heart.
This Croatian idiom means "in person" or "he himself," and "glavom" is part of the expression representing someone's presence.
Glavom i bradom, to je bio on.
He himself, in person, that was him.
In this sentence, "glavom" refers to the literal use of his head hitting an object.