An admiral is to be admired, but the words have nothing in common except a letter. In this post, I'll only explain the formal word; stay tuned for the latter. Admiral (meaning "commander") can be traced farthest back to the Arabic word amir, defined as "prince". Etymologists haven't bothered tracing this back to languages like Semitic or (even further back) Afro-Asiatic, but the correlation is clear: a Hebrew word, aluf, also means "commander", and is probably related. Anyway, amir (which is still present as an English word today, more commonly as emir), was later borrowed by the French as amiral ("commander of naval forces"), which became the current term admiral. But how did the d get inserted so surreptitiously? Folk etymology! We already had the word admirable, and people just assumed that the word for "powerful naval leader" came from admirable because he is one, so they 'corrected' the word to admiral. What a swimmingly buoyant etymology!
Adam Aleksic, a rising sophomore studying linguistics and government at Harvard University, has been described as the internet's sixth most famous etymologist. He also has disturbing interests in politics, vexillology, geography, board games, conlanging, and law.