The g in gnat is silent now, and it was not always. Old English gnæt was pronounced with both consonants sounded, a gn- cluster that English speakers managed without difficulty until the 1600s or so. The spelling was fixed before the sound was lost, so the letter stayed behind as a record of a pronunciation nobody has used in four hundred years.
This is the genuine kind of silent letter, and it is worth keeping distinct from the fake kind. The g in gnat, the k in knee and the w in wrist all record real speech. The b in debt does not — it was inserted by scholars pointing at Latin. Gnat itself is probably related to gnaw, and may have meant something like "biting insect," which a fourteenth-century translator confirmed at length: the gnat, he wrote, has a pipe in its mouth like a prick, and wakes sleeping men with noise and biting.
gnat (n.) Old English gnæt "gnat, midge, small flying insect," earlier gneat , from Proto-Germanic *gnattaz (source also of Low German gnatte , German Gnitze ); perhaps literally "biting insect" and related to gnaw . The gnatte is a litil fflye, and hatte culex he soukeþ blood and haþ in his mouþ a pipe, as hit were a pricke. And is a-countid a-mong volatiles and greueþ slepinge men wiþ noyse & wiþ bytinge and wakeþ hem of here reste. [John of Trevisa, translation (late 14c.) of Bartholomew Glanville's "De proprietatibus rerum" ] Gnat-catcher , insectivorous bird of the U.S. woodlands, is from 1823.
gnat came in through Old English, and its spelling follows that family's conventions.
How that family writes these sounds
| /n/ at the start | kn- or gn-. The first letter is silent now and was not in 1400knee, knight, gnaw, gnat |
What gives it away on the page
| kn-, gn-, wr- | Silent now, fully pronounced in 1400. The letters are a recording of a lost pronunciation.knight, gnat, wrist |
Old English in the spelling guide · guess another word's family