1798, "full of patches; spotty, occurring only in patches," from patch (n.1) + -y (2). Related: Patchiness.
Entries linking to patchy
patch n.1
"piece of cloth used to mend another material," late 14c., pacche, of obscure origin, perhaps a variant of pece, pieche, from Old North French pieche (see piece (n.1)), or from an unrecorded Old English word (Old English had claðflyhte for "a patch").
Meaning "portion of any surface different from what is around it" is from 1590s. That of "small piece of ground," especially one under cultivation, is from 1570s. As "small piece of plaster used on the face," to cover blemishes or enhance beauty is from 1590s. Phrase not a patch on "nowhere near as good as" is from 1860.
-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.