Bad omen.
Dream dictionary: Sword, breaking it dream meanings
…If we break any object which means servitude or dependence its equivalent to the release of these ties. To dream that a water-filled vessel breaks and pours on the ground indicates the definitive loss of affection. Breaking a sword means our victory over our enemies (if the sword is theirs) or our own loss (if it’s our sword). Breaking a necklace means our release of another person….
To dream of breaking an object means servitude or dependence equivalent to the liberation from difficult situations. To dream of breaking a full glass of water that shatters on the floor indicates a definite loss of affection. To dream about the breaking of the sword of our enemies indicates our victory over them. To dream that a necklace breaks signifies our liberation from a negative relationship.