spiny (adj.)

c. 1400, "backbone," later "thornlike part" (early 15c.), from Old French espine "thorn, prickle; backbone, spine" (12c., Modern French épine), from Latin spina "backbone," originally "thorn, prickle" (figuratively, in plural, "difficulties, perplexities"), from PIE *spe-ina-, from root *spei- "sharp point" (see spike (n.1)). Meaning "the back of a book" is first attested 1922.

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.