This is the 6278th most frequent Russian word.
ума
"Ума" is the genitive or singular form of "ум," meaning "mind" or "intelligence."
Here, "ума" refers to one's mental faculties or reasoning.
Он пришёл в ум от услышанного.
He regained his reason after hearing that.
Here, "ума" is used to signify wisdom or intellect.
Он пошёл на ум к старому философу.
He went to seek wisdom from the old philosopher.
"ума" in this case relates to thoughts or ideas a person might have.