to one's face; in one's presence
Used when saying or doing something directly in front of someone, often with a nuance of bluntness or without hesitation. Common in phrases like 向き付けに言う.
He argued back to his boss's face.
I was deeply hurt when someone said bad things about me to my face.
The word is composed of 向き (muki, 'direction' or 'facing') and 付け (tsuke, 'attaching'), with the adverbial particle に. The exact historical derivation is uncertain, but it likely developed from the idea of 'facing directly toward someone'.