This phrase means to be hostile to each other. It comes from a time when quarrels were settled by fights with daggers. The expression is first recorded by 1668 but common only from the nineteenth century.

Übersetzung:

mit jemandem auf Kriegsfuß stehen

Gegenteil(e)

The opposite of "be at daggers drawn with somebody" is "to bury the hatchet" or "to make one's peace with somebody".

Synonym(e):

You could also say: to be in conflict with somebody.