Guide shows the French gu- convention, inserted to keep the g hard before a front vowel, exactly as in guard, guest and guile. English took it in the late 1300s from Old French guider, "to lead, conduct."
Underneath the French, the word is Germanic again. Old French got it from Frankish witan, "to show the way," from a Proto-Germanic verb meaning to look after or watch over, from an Indo-European root meaning "to see" — the same root behind wit, wise and vision. English already had the native descendant of that root in witan, "to know." So guide is a Germanic word that went to France, picked up a French spelling and a French shape, and came back looking foreign enough that English never noticed the relation. The French form was further influenced by Old Provençal or Italian versions of the same word.
guide (v.) late 14c., "to lead, direct, conduct," from Old French guider "to guide, lead, conduct" (14c.), earlier guier , from Frankish *witan "show the way" or a similar Germanic source, from Proto-Germanic *witanan "to look after, guard, ascribe to, reproach" (source also of German weisen "to show, point out," Old English witan "to reproach," wite "fine, penalty"), from PIE root *weid- "to see." The form of the French word influenced by Old Provençal guidar (n.) "guide, leader," or Italian guidare , both from the same source. Related: Guided ; guiding . Guided missile , one capable of altering course in flight, is from 1945. also from late 14c. guide (n.) mid-14c., "one who shows the way," from Old French guide , 14c., verbal noun from guider (see guide (v.)). In book titles from 1610s; meaning "book of information on local sites" is from 1759. In 18c. France, a "for Dummies" or "Idiot's Guide to" book would have been a guid' âne , literally "guide-ass." Guide-dog for the blind is from 1932. also from mid-14c.
guide 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