It means to be in dispute with somebody. Originally someone who was called a loggerhead was a stupid person. Shakespeare used it that way in 1588. A logger was a thick block of timber which was fastened to a horse's leg to prevent it from running away. In the seventeenth century, a loggerhead was also recorded as an iron instrument used for melting pitch. It is likely that the use of these tools as weapons was what was being referred to when rivals were first said to be 'at loggerheads'.

Übersetzung:

mit jemandem auf Kriegsfuß stehen

Gegenteil(e)

The opposite of "to be at loggerheads" is "to be of one mind".

Synonym(e):

You could also say: to be in irreconcilable disagreement.