"like a pillow, soft, yielding," 1798, from pillow (n.) + -y (2).
Entries linking to pillowy
pillow n.
"a head-rest used by a person reclining," especially a soft, elastic cushion filled with down, feathers, etc., Middle English pilwe, from Old English pyle "cushion, bed-cushion, pillow," from West Germanic *pulwi(n) (source also of Old Saxon puli, Middle Dutch polu, Dutch peluw, Old High German pfuliwi, German Pfühl), an early borrowing (2c. or 3c.) from Latin pulvinus "little cushion, small pillow," of uncertain origin. The modern spelling in English is from mid-15c.
Pillow fight (n.) "mock combat using pillows as weapons" is attested from 1837; slang pillow talk (n.) "relaxed intimate conversation between a couple in bed" is recorded by 1939. Pillow-case "washable cloth drawn over a pillow" is by 1745. Pillow-sham is by 1867.
-y 2
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.