The opposite or antonyms for the phrase 'were cautious' can vary depending on the context of the sentence. In some cases, antonyms could be described as being reckless, impulsive, carefree, or carelessly casual. Other examples, could include terms like impetuous, audacious, hasty, or overconfident. It could also depend on the level of caution that was present in the initial situation. In some cases, antonyms could include adjectives like bold, daring, confident, or daringly adventurous. Ultimately, the opposite of being cautious can be seen as acting without much thought or deliberation, often leading to negative consequences.