Guest is a native word that Norse pulled sideways. Old English had giest, and by ordinary sound changes it should have come through to modern English as something like yest. The hard g it actually has was borrowed from the Old Norse cognate gestr — the same interference visible in give, get and gift.
The word's deep history is one of the best things in etymology. It comes from an Indo-European root meaning stranger, guest and host all at once, and the same root gives Latin hostis — which meant "stranger" in early use and "enemy" in classical Latin. The underlying idea seems to be someone with whom you have reciprocal obligations of hospitality; whether that made them a guest or an enemy depended on how it went. English hospitality and hostile are two ends of one word.
guest (n.) Old English gæst , giest (Anglian gest ) "an accidental guest, a chance comer, a stranger," from Proto-Germanic *gastiz (source also of Old Frisian jest , Dutch gast , German Gast , Gothic gasts "guest," originally "stranger"), from PIE root *ghos-ti- "stranger, guest, host" (source also of Latin hostis , in earlier use "a stranger," in classical use "an enemy"); the root sense, according to Watkins, probably is "someone with whom one has reciprocal duties of hospitality." Spelling evolution influenced by Old Norse cognate gestr (the usual sound changes from the Old English word would have yielded Modern English *yest ). Meaning "person entertained for pay" (at an inn, etc.) is from late 13c. Old English also had cuma "stranger, guest," literally "a comer." Phrase be my guest in the sense of "go right ahead" first recorded 1955. guest (v.) early 14c., "receive as a guest;" 1610s, "be a guest;" 1936, American English, "appear as a guest performer," from guest (n.). Related: Guested ; guesting . also from early 14c.
guest came in through Norman French, and its spelling follows that family's conventions.
How that family writes these sounds
| hard /g/ before e or i | gu-, with a u wedged in to keep the g hardguard, guest, guide, guile |
What gives it away on the page
| gu- | A u inserted to keep the g hard before a front vowel.guard, guest, guide, guile |
Norman French in the spelling guide · guess another word's family