A name for shameful fear
In present-day English a coward is a person who, in a way others treat as disgraceful, will not face danger, pain, or difficulty. The word can still be used as an adjective, though cowardly is now the ordinary form. The charge is moral as well as physical. It does not merely register fright. It accuses someone of shrinking from what the speaker thinks ought to be met.
That charge has been stable for centuries. The origin of the word coward is not a native English invention, and the picture of fear packed into it is older than the modern spelling.
Borrowed in the thirteenth century
English took the noun in the 1200s from Anglo-French and Old French forms such as couard, coart, cuard, and couart. Standard dictionaries place first English use in the thirteenth century; several etymological surveys put it in the middle of that century. On the Continent the French word is already visible around 1100, in the Song of Roland, spelled cuard.
The loan arrived with a crowd of Middle English spellings: couard, couward, cowart, cowerde, cuward, and more besides. Anglo-Norman writing uses the word both as a noun for a person without bravery and as an adjective meaning timid. French later kept couard, but it is no longer the everyday term there. Poltron, taken from Italian, and lâche have done most of that work for a long time.
The English spelling that begins with cow is not evidence that the insult comes from the animal. Later commentators have often tried to drag it toward cowherd, or toward the verbs cow and cower. Those are separate histories. Cower is Germanic, from Scandinavian. The family name Coward, recorded from the same thirteenth-century stretch, usually continues Old English cuhyrde, a cow-herd, and is a homonym rather than the same word. The look of the common noun was probably pulled toward cow as verb and noun, which made the false story easier to believe.
English already had a native word for the quality. Old English earg covered much of the same ground and survives only in northern dialect as argh. When French vocabulary for character and conduct poured into Middle English, the borrowed noun largely replaced that older stock.
Tail plus a scornful ending
The French word is built in two pieces. The first is coe, coue, or cue, older forms of the noun that became modern French queue, meaning tail. That noun goes back to Latin cauda, with a popular variant coda. From the same Latin stock English later received coda and caudal, and, through French, queue and one sense of cue.
The second piece is the suffix -ard or -art. In medieval French it marked a person by a quality or habit, often with contempt. The same ending appears in drunkard, sluggard, laggard, and dastard, and in the fox-name Reynard. Put together, couard is a tail-person: someone characterized by a tail in a way the speaker finds ridiculous or shameful.
How the tail was meant is the part no careful account will lock down. One reading is an animal that turns tail and flees. Another is the posture of a frightened dog or other beast with the tail clamped between the legs, a picture still alive in the English phrase about having one's tail between one's legs. Heraldry keeps a related image: a lion coward is drawn with the tail doubled between the legs, a mark of disgrace on the shield. French lexicography has also explained the formation as one who carries the tail low. Historical dictionaries treat the exact animal or military picture as uncertain. All of those readings share a body language of flight. None of them has to be the single original joke.
A further public clue sits in the Reynard cycle. In Old French versions the hare is named Coart; later English and Flemish tellings keep variants such as Cuwaert and Kywart. Hares bolt. Naming the hare after the tail-word made the metaphor familiar long before English spelling settled.
Italian codardo and Spanish cobarde, the latter from older couarde, came from the French word rather than independently from Latin. Portuguese covarde and Catalan covard belong to the same cluster. The Latin noun itself may rest on a Proto-Italic form. Some etymologists connect that form, tentatively, with a root meaning to strike or split, and compare Latin cudo, to beat, and caudex, a tree trunk or stump. That deeper step is not agreed, and it does not change the medieval story.
What the sense did and did not do
From its first English uses the noun already meant a person without courage. By the late thirteenth century it was also an adjective, timid or lacking heart. The heraldic sense, a beast shown with the tail between the legs, is a technical survival of the same image rather than a later twist of character. An obsolete verb, to coward someone, once meant to intimidate. It did not last.
What did not happen is a slow slide from a concrete tail to an abstract vice. French speakers were already using the formation as a moral insult when English borrowed it. English inherited the insult, then dressed the spelling in a way that invited folk etymology. The modern word still carries the old animal picture even when no one hearing it thinks of a tail.
The useful detail to keep is a date and a false friend. By about 1100 French already had cuard. By the mid-1200s English had the loan. The English family name Coward looks identical and is usually a cowherd in origin. The insult and the occupation met only on the page.