1520s, "resembling or having the nature of slate," from slate (n.) + -y (2). By 1824 in reference to a taste of some wines.
Entries linking to slaty
slate n.
mid-14c. (c. 1300 in Anglo-Latin), sclate, "tile or slate used principally in roofing," from Old French esclate, fem. of esclat "split piece, splinter" (Modern French éclat; see slat). So called because the rock splits easily into thin plates.
As an adjective, 1510s. As a color, by 1813 (slate-gray is from 1791 in dyeing, later in bird descriptions; slate-colour is from 1743, slate-blue from 1792).
The sense of "a writing tablet" (made of slate), is recorded by late 14c. and led to that of "list of preliminary candidates prepared by party managers," attested from 1842, from notion of being chalked on a slate and thus easily altered or erased. Clean slate "fresh beginning of a state of affairs" (1856) is an image from customer accounts chalked up in a tavern.
-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.