before vowels myc-, word-forming element meaning "mushroom, fungus," formed irregularly from Latinized form of Greek mykēs "fungus, mushroom, anything shaped like a mushroom," a word of uncertain origin (Beekes doubts the traditional explanation that connects it to the source of mucus). The correct form is myceto- (mycet-).
late 14c., from Old English gesnot "nasal mucus," from Proto-Germanic *snuttan (source also of Old Frisian snotta, Middle Low German and Middle Dutch snotte, Middle Low German snute), from the same base as snout. Old English had also a verb snite "wipe or pick one's nose." Meaning "despicable person" is from 1809.
type of small fish, 1774, from Latin blennius (in Pliny), from Greek blennos, from blenna "slime, snot, mucous discharge," so called for the coating on its scales (from PIE *mled-sno-, suffixed form of root *mel- (1) "soft"). "The Blennies (B. gattorugine and allied species) are little fishes common in the rock pools, often called Butterfishes from the slime or mucus which they exude. Hence their name" [Thompson, "A Glossary of Greek Fishes"].
Old English clæg "stiff, sticky earth; clay," from Proto-Germanic *klaijaz (source also of Old High German kliwa "bran," German Kleie, Old Frisian klai, Old Saxon klei, Middle Dutch clei, Danish klæg "clay;" also Old English clæman, Old Norse kleima, Old High German kleiman "to cover with clay").
Some sources see these as being from a common PIE root meaning "slime; glue" also forming words for "clay" and verbs for "stick together." Compared words include Latin gluten "glue, beeswax;" Greek gloios "sticky matter;" Lithuanian glitus "sticky," glitas "mucus;" Old Church Slavonic glina "clay," glenu "slime, mucus;" Old Irish glenim "I cleave, adhere;" Old English cliða "plaster." But Beekes writes that "Not all comparisons are convincing," and notes that most words cited are from Balto-Slavic or Germanic, "which suggests European substrate origin."
In Scripture, the stuff from which the body of the first man was formed; hence "human body" (especially when dead). As an adjective, "formed of clay," 1520s. Clay-pigeon "saucer of baked clay used as a flying target in trap-shooting," in place of live birds, is from 1881. Feet of clay "fundamental weakness" is from Daniel ii.33.
mid-15c., mokken, "make fun of," also "to trick, delude, make a fool of; treat with scorn, treat derisively or contemptuously;" from Old French mocquer "deride, jeer," a word of unknown origin. Perhaps from Vulgar Latin *muccare "to blow the nose" (as a derisive gesture), from Latin mucus; or possibly from Middle Dutch mocken "to mumble" or Middle Low German mucken "grumble." Perhaps ultimately it is imitative of such speech. Related: Mocked; mocking. Replaced Old English bysmerian. The sense of "imitate, simulate, resemble closely" (1590s, as in mockingbird ; also see mock (adj.)) is from the notion of derisive imitation.