The Spanish flojo means “slack, loose” — but it is a very common word in Spanish, often used to mean “relaxed” in a negative way, in senses like, “They cut themselves some slack.”
Flojo comes from the Latin fluxus, meaning the same as the Spanish. From fluxus, we get a bunch of English words, including: fluent, fluid, fluctuate and even (via fluent) affluent and influence. We also get the more fun flush and the most obvious flux (as in, “to be in flux.”) All of these can be understood in the sense that, that which is loose flows — and all of these words flow in one way or another: liquids are fluid, you speak fluently, flushing water flows, money flows if you are affluent, etc.
The -x- in the original Latin tended to disappear into the English (hence leaving the vowels before and after, as in fluent or fluid) or became a -sh- sound. This is an example of the common pattern of the -sh- sounds mapping to the throat-clearing -j- in Spanish, with the fl-sh of flush mapping to the fl-j of flojo.
Ajedrez (Spanish for “chess”) sounds nothing like the English chess, so they can’t be first cousins… right?
Wrong. The Spanish “j” sound — pronounced with an Arabic-ish throat-clearing sound — was originally pronounced with a “sh” or “ch” sound. The arabic influence changed the pronunciation to be closer to the arabic: see sherry/jerez, for example.
Ajedrez and Chess are another example of this same interesting pattern. Try to imagine the “j” in ajedrez with a ch- sound and you almost get chess.
Both, curiously, come from the same Sanskrit word for the game: chaturanga (so the English ch- is thus preserved closer to the original sound — English didn’t have the arabic influence that Spanish did). And these came to both languages via the Persian, chatrang. The traders and travelers, after all, are the ones who change languages.
The Spanish celoso and the English for the same, jealousy, come from the same Greek root: zelos.
But how did this happen? They should so different!
The answer is that the Latin (and Greek) words with a -ch- sound and variations (like -sh-, the soft -j-, -z-, etc) usually turned into the hard, guttural, throat-cleaing -j- sound in Spanish. Think about sherry and jerez, for example, or quash and quejar, or soap and jabón.
Thus, the c-l-s of celoso maps to the j-l-s of jealous.
Curiously, the ancient Greek form — zelos — meant jealousy, but in the more positive sense of enthusiasm and friendly rivalry. In a word: zeal — which also comes from the same root!
The Latin sounds for “sh” — and similar variations, like “ch” and “ss” — became a “j” sound in Spanish.
Thus, the English sherry is near identical to the Spanish jerez!
These sh/j sounds were often spelt with a “x” in old Spanish; and sherry itself is named after the town it first came from, Xeres, which is near Cordova.
Embassy (and Ambassador) and its Spanish equivalent, Embajada (and Embajador), both come from the same ancestor, the Old French Ambactos.
What is most interesting about these two is that it is an example of the pattern where the -j- sound in Spanish maps to the -sh- sound (and its cousins, like -ss- and -ch-) in English. Remember syrup and jarabe, chess and ajedrez, sherry and jerez, and push and empujar for a few examples.
Thus, the m-b-j of emabajada maps to the m-b-ss of embassy.