Loyal

Loyal, as defined by the American Heritage College Dictionary, means "steadfast in allegiance to one's homeland, government, or sovereign, faithlful to a person, ideal, custom, or duty, or of, relationg to, or marked by loyalty." Loyal originated from the Latin word legalis (legal) which is from the Latin roots lex-, leg-. Then it went through Old French as leial, loial and on to French and into English as loyal. Loyal and legal are also doublets because they share the same stem, lex-.

It is easy to see how the word passed through French. The French version dropped the consonant between e and a, while also losing its ending.