1440, "lax, flaccid, soft, tender," from O.Fr. lasche "soft, succulent," from laschier "loosen," from L.L. laxicare "become shaky," related to L. laxare "loosen," from laxus "loose" (see
lax). Sense of "luxuriant in growth" is first attested 1610; erroneously applied to colors since 1744.