The term 'most natal' implies something that pertains to birth or origins. Therefore, antonyms for this phrase would be words that signify anything other than where someone or something is from. These antonyms could include terms such as foreign, outward, new, strange, or synthetic. The term foreign refers to something that is not native or local, and outward alludes to something that is external or visible. New implies something that has just been introduced or created, while strange signifies anything unfamiliar or unusual. Lastly, synthetic suggests a man-made material that is not natural or organic. In summary, the antonyms for "most natal" include words that denote non-native, external, unfamiliar, artificial, and more.