The term "strait-laced" is often used to describe someone who is overly serious, traditional, and conservative in their attitudes and behavior. Antonyms for this word may include "carefree," "uninhibited," and "spontaneous." A person who is carefree is often thought of as being lighthearted and not overly concerned with rules or expectations. Someone who is uninhibited may be freer with their expressions of emotion and willingness to participate in new experiences. A spontaneous person is often impulsive and in the moment, acting without too much thought or deliberation. All of these words represent traits that are the opposite of someone who is "strait-laced," and each suggests a person who is more adventurous and open-minded.