"viscous adhesive substance," early 13c., from Old French glu "glue, birdlime" (12c.), from Vulgar Latin *glutis or Late Latin glutem (nominative glus) "glue," from Latin gluten "glue, beeswax," from PIE *gleit- "to glue, paste" (source also of Lithuanian glitus "sticky," glitas "mucus;" Old English cliða "plaster"), from root *glei- "clay," also forming words with a sense of "to stick together" (see clay). Formerly also glew. In reference to glue from boiled animal hoofs and hides, c. 1400. Glue-sniffing attested from 1963.
adjective suffix, "full of or characterized by," from Old English -ig, from Proto-Germanic *-iga- (source also of Dutch, Danish, German -ig, Gothic -egs), from PIE -(i)ko-, adjectival suffix, cognate with elements in Greek -ikos, Latin -icus (see -ic). Originally added to nouns in Old English; used from 13c. with verbs, and by 15c. even with other adjectives (for example crispy).