Antonyms for the phrase "hast sneaking suspicion," which means having a strong but unconfirmed feeling or belief about something, include "assurance," "certainty," "convinced," and "confident." These words suggest a high degree of certainty and lack of doubt, unlike the cautious and uncertain feeling conveyed by "sneaking suspicion." Other antonyms include "knowledge," "proof," "evidence," and "fact," all of which imply a logical or scientific basis for one's belief or feeling. Using antonyms of "hast sneaking suspicion" can help clarify one's confidence level and convey a sense of conviction or certainty in one's beliefs.