Most straightlaced refers to someone who is extremely strict, conservative, and traditional. The antonyms for this expression include words like liberal, unconventional, and free-spirited. A liberal person is someone who is open-minded, progressive, and willing to break social norms. An unconventional person is someone who likes to challenge traditional ideas and practices. A free-spirited individual is someone who is carefree, non-conformist, and independent. All of these antonyms represent a departure from the straightlaced lifestyle and are often associated with more open, creative, and adventurous approaches to life. Overall, the antonyms for most straightlaced describe people who live life on their own terms, rather than conforming to societal expectations.