To be in disagreement, opposed

All the members of the committee were at odds. They kept arguing all day long and couldn't come up with an agreement

I membri del comitato erano in totale disaccordo tanto che, dopo aver discusso per tutto il giorno, non hanno raggiunto nessun accordo

Administrators and officials are at odds on how to finance the new health plan

Amministratori e funzionari sono in contrasto su come finanziare il nuovo piano di assistenza sanitaria

I know he changes his mind very often according on which way the wind is blowing, but what he's saying today is completely at odds with what we agreed on yesterday in my office

So che è una banderuola e cambia idea secondo come tira il vento, ma quello che afferma oggi è in totale contrasto con quello che abbiamo concordato ieri nel mio ufficio

The origin of this phrase is not clear. One theory associates it to the concept of odd and even, where things that are even are equal and things that differ are odd