Profitably is from profitable (from profit, from Latin profectus 'progress, profit', from proficere 'to make progress, advance') + the adverbial suffix -ly. Important recorded forms include profectus (Latin) and proficere (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 in a way that produces profit or advantage. The wider family includes related words such as profit, profitable, and profitableness.