Took a stab can be interpreted as an attempt made to show uncertainty or a lack of confidence in oneself. To the contrary, there are multiple antonyms one could use to explain the opposite of taking a stab. Words such as definite, confident, decided, and certain can be used to describe someone who is sure of themselves and has no hesitation in their actions. Other antonyms could include clear, obvious, known, or established, which can be used to explain a situation or outcome that has been predetermined or is not up for debate. At the end of the day, taking a stab and its antonyms are all about displaying a level of certainty in one's actions or beliefs.