Puny is from Anglo-French puisné and Old French puisné ('born later, younger'), from puis ('afterward') + né ('born'), from Latin natus. The sense shifted from 'junior' to 'small, weak'. Important recorded forms include puisné (Old French), post (Latin), and natus (Latin). Morphologically, the word preserves a built structure whose named elements carry the historical sense into English. The modern sense remains close to that composition, with the parts narrowing into a single lexical item. In current use it covers small, weak, or insignificant. The wider family includes derived forms such as puniness and punily and related words such as puisne.