grubby (adj.)

"larva of an insect," early 15c., perhaps from grub (v.) on the notion of "digging insect," or from the possibly unrelated Middle English grub "dwarfish fellow" (c. 1400). Meaning "dull drudge" is 1650s. The slang sense of "food" is first recorded 1650s, said to be from birds eating grubs, but also often linked with bub "drink."

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). Adjectives such as hugy, vasty are artificial words that exist for the sake of poetical metrics.

"sloppy, shabby," 1965, American English slang, perhaps based on, or blended from, grubby and dingy.