Interestingly, though, it appears, though, that there is no such proto-form for "left". It has been hypothesized that this may have been due to the taboo nature of all things left in ancient times. But, whatever the reason, this has resulted in a number of different and unrelated roots based on local dialect forms, and ultimately in largely unrelated modern day words for left. The English word ”left”, for example, is derived from the Old English word “lyft”, which originally meant idle, weak, useless or foolish.
It is notable that, in English and in several other European languages, the word “right” is also used to mean correct, fair or proper. However, the use of “right” as the opposite of wrong, as well as the opposite of left, is, in linguistic terms at least, pure coincidence, and the words developed quite separately and from unrelated roots. In the same way, the homophonic coincidence of “write” and “right” (a pun which occurs in no other European language) is just that, a coincidence.
The Latin word for left, “sinistra”, also came to mean unlucky or unfortunate to the Romans, and this double meaning was passed down to English and several other Latin-derived languages in the word “sinister”, with all its connotations of evil, harm and threat. Another Latin word for left, “laevus”, also had a double meaning of silly or unlucky. On the other hand, the Latin for right, “dexter”, also carried connotations of skillful, fortunate, favourable, etc, and the English word “dexterity”, meaning manual skill, is derived directly from it. Even the word “ambidextrous” effectively means right-handed on both sides. “Ambisinistrous” (left-handed on both sides) means clumsy and having equally bad ability in both hands.
The French word for right, “droit”, also means straight, upright and upstanding, and as a noun it means law, authority and justice, all embodying positive values ( as does the English word “adroit” which it has given rise to). On the other hand, the French word for left, “gauche”, also means (as in its English usage) awkward and clumsy. To mention just a couple of other examples, “mancino”, the Italian word for left-handed also means treacherous or deceitful, and the German word for left, “linkisch”, also means awkward, but such negative associations also occur in several other languages.
Almost across the board and since ancient times, then, the word “right” has always been associated with the good and the skillful, while “left” has had connotations of clumsiness or even evil. This is perhaps even more clear when one looks at the pejorative use of the word “left” and "left-handed" in some English phrases. A “left-handed compliment”, for example, is one that is unflattering or insincere; a “left-handed wife” is an old English phrase for a mistress; a “left-handed marriage” is one of social unequals, doomed to failure; a “daughter of the left hand” or “born on the left side of the bed” is a child born out of wedlock; “two left feet” indicates a clumsy and unskillful dancer; a “left-handed opinion” is a weak one; a “left-handed dream” is a nightmare; “left-handed wisdom” implies faulty reasoning; etc, etc. Although many of these phrases are now considered archaic and little-used, the trend is clear.
Many of the English words or phrases used to describe left-handedness itself are similarly uncomplimentary. A 1987 report in The Economist magazine listed the following colourful slang and dialect words: “buck-fisted”, “cack-handed”, “caggy-handed”, “clicky-handed”, “corrie-pawed”, “cow-pawed”, “cuddy-wifter”, “dolly-pawed”, “gar-pawed”, “gibble-fisted”, golly-handed”, “keck-fisted”, “keggy-handed”, “left-plug”, “left-kelly”, “loofer”, “scoochy”, “scrammy-handed”, “skiffle-handed”, “south-pawed”, “spuddy-handed” and “squiffy”. “Cack-handed” in particular (and its derivatives “caggy-handed”, “keck-fisted”, etc) is derived from the Latin cacere, to defecate, and carries with it derogatory connotations of the use of the left-hand in some countries to clean oneself after defecation.
There are, or at least were, many other regional terms for left-handedness not mentioned in this list, including “gammy-fisted”, “ballock-handed”, “scrummy-handed”, “kay-pawed”, “cawk-fisted”, “bang-handed”, squivver-handed”, “cunny-handed”, etc. The English Dialect Survey, carried out in the 1940s, identified 87 distinct terms. The Linguistic Survey of Scotland from around the same time, listed many more, including “flug-handed”, “clootie-handed”, “kippie-handed”, pallie-handed”, etc.