Speak daggers phrase
To use harsh words or foul language when speaking to someone to upset them.
John tends to speak daggers to his employees when they made mistakes, even the smallest ones.
That cantankerous boy has no friends because he is always speaking daggers.
Their spoiled son spoke daggers to them and marched off.
I have never spoken daggers to anyone because I know that no one wants to receive a spiteful remark.
The verb "speak" must be conjugated according to its tense.
The origin of this phrase is not clear.