This is the 1151st most frequent Japanese word.
勝手
"勝手" (katte) means "selfish," "arbitrary," or "one's own convenience." It can also refer to a kitchen or circumstances.
The word "勝手" is used to indicate selfish or arbitrary behavior, often with a negative connotation.
そんな勝手な行動は許されません。
Such selfish actions are not allowed.
The word "勝手" here references familiarity or proficiency with something, in this case, cooking.
彼女は料理の勝手を知っている。
She knows her way around cooking.
In this sentence, "勝手に" is used adverbially to mean 'arbitrarily' or 'without permission.'