The antonyms for the word "off-colour" are vibrant, colorful, healthy, robust, and lively. Vibrant refers to bright and strong colors, signifying a liveliness that indicates vitality and vigor. Colorful denotes an abundance of different colors, creating a lively visual experience. Healthy refers to a state of well-being, free from any disease or ailment. Robust relates to being strong, sturdy, and physically fit. Lively pertains to a sense of energy, activity, and excitement. Therefore, by using these antonyms, one can replace the negative connotation of off-color and express a positive viewpoint with the given context.