A word for what fits
In present-day English, good names almost any kind of approval. It can mean morally right, technically sound, pleasant, large enough, still usable, or simply acceptable as a reply. A meal, a witness, a stretch of road, and a person who keeps a promise can all be good without sharing a single trait except this: they match what the situation asks for.
The origin of the word good is native. English did not borrow it from French or Latin. It arrived as part of the Germanic stock that became Old English, and it has stayed in continuous use ever since.
From Old English into the present
Old English already had gōd, with a long vowel, in the period before 1150. Middle English kept it as good, god, gode, and related spellings. The modern form is a direct continuation, not a replacement. The Oxford English Dictionary treats the adjective, the noun, and even a now-rare verb as inherited from that Old English layer.
The same adjective is found across the old Germanic languages. Old Frisian used god, Old Saxon gōd, Old Norse góðr, Middle Dutch and Dutch goed, Old High German guot, German gut, and Gothic gōþs. Scots guid is the northern English cousin. That pattern is what inheritance looks like: sister forms in related languages, not a single late loan spreading from a court or a schoolbook.
The noun rode along with the adjective. Old English gōd could mean a benefit, a gift, virtue, or property. The last of those senses is why English still speaks of goods as belongings or merchandise, a use that matches German Gut for an estate or an item of property.
A Germanic adjective, a cautious Indo-European step
Linguists reconstruct a Proto-Germanic adjective *gōdaz (sometimes cited as *gōda-). Its older meaning is usually given as fitting or suitable, rather than kind or holy. One line of reconstruction, associated with Guus Kroonen, treats the form as a derived adjective from an otherwise unattested verb *gadaną, itself from a Proto-Indo-European root *gʰedʰ- with a range around uniting, associating, or suiting. That deeper step is a hypothesis. Dictionaries that print it also hedge: the Germanic word is secure; the Indo-European parent is not proven beyond dispute.
If the proposed root is real, English has quieter relatives nearby. Gather comes from Old English gædrian. Together belongs with that cluster. Old English also had companion words such as gada and gædeling, names for someone who belongs with you. Outside Germanic, the same family is often illustrated with Sanskrit gadh- (to seize or cling), Old Church Slavonic godu for a favorable time, Russian godnyi for fit or suitable, and Lithuanian goda for honor. Slavic words on god- frequently sit near fitness, a proper season, or something that pleases. Russian god, now year, is sometimes traced to a proper season for work, though that path is an inference, not a recorded first sense.
A comparison with Greek agathos, once offered and later dropped, does not hold. Direct borrowing from Greek into Germanic is phonologically impossible on the usual sound correspondences, and the Slavic evidence makes a Greek loan into two branches even less plausible.
God is a different word. Folk history has long tried to derive the name of the deity from this adjective. The forms do not line up, and the ethical coloring of good is comparatively late. The two traveled in the same language without being kin.
How the senses opened out
Old English gōd already covered more than one shade: excellent, valuable, complete; of actions, beneficial or effective; of persons, righteous or pious. The likely older layer is still visible there: having the quality that is wanted.
Kindness is a later tint. Late Old English could use the word of persons, and of God, in the sense of benevolent. By the mid-fourteenth century that sense applied to actions as well. Around 1200 the adjective could mean friendly or gracious. A Middle English sense of holy survives in Good Friday, where the word does not mean pleasant.
Competence is old too. Late Old English could call someone good in a craft. Modern English usually says good at; Middle English more often used of or to. From about 1200 the word also stretched over size and span: a large number, a long time, a long way. A good while is recorded from about 1300. Coin that was good, from the late fourteenth century, was money of full value, not debased. Children called good, meaning well-behaved, appear by the 1690s. As a cry of satisfaction, the word is found from the early fifteenth century.
Set phrases keep older legal and moral work. Make good as repayment or atonement is late fourteenth century. As good as, meaning virtually, is mid-fourteenth. For good, permanently, is recorded from 1711, shortened from for good and all. The noun sense of the good side of something is later, from the 1660s.
None of this is a fall from a purely moral height. The ethical uses grew beside, and often after, the sense of fitness.
Better from a different stem
English does not say gooder. The comparative better and the superlative best belong to another Germanic root, *bat-, the same family as Old English bōt, a remedy or advantage that survives in the phrase to boot. Proto-Germanic had a comparative *batizô and a superlative *batistaz. Those forms were attached to good, and sometimes to well. Latin shows a similar split in bonus, melior, optimus: the everyday positive and the higher degrees do not share a stem.
The positive adjective *bataz itself did not survive as a common English word. That is why better no longer feels like a stranger. It is a leftover from a scale of improvement that English kept only in the comparative and superlative. The adjective good stayed simple: no prefix, no transparent inner parts, with goodness and the separate adverb well sitting around it rather than inside it.
The durable fact is that split. When English needs a higher degree, it still reaches for better, a form that once measured advantage, not for a regular comparative of good.