adj

• (US) Excessively sweet, emotional, nostalgic; cheesy; mushy. (British equivalent: soppy)
  "He was a good deal of a character, and much better company than the sappy literature he was selling."
• (obsolete) Juicy.
  "1590, Edmund Spenser, The Faerie Queene, Book Two, Canto XII, Stanza 56, edited by Erik Gray, Hackett, 2006, p. 214, In her left hand a Cup of gold she held, And with her right the riper fruit did reach, Whose sappy liquor, that with fulnesse sweld, Into her cup she scruzd, with daintie breach Of her fine fingers, without fowle empeach, That so faire winepresse made the wine more sweet:"
• (obsolete, of wood) Spongy; Having spaces in which large quantities of sap can flow.
  "In flush-framing if is observable, that the failure of all timber in old buildings has commenced much sooner than they otherwise would have done, owing to the sappy wood being at the corners of the principal beams, which soon decays, as its spongy quality attracts the moisture; whereas the heart, espescially of oak, will be as sound as the first day it was used."

adj

• (obsolete) Musty; tainted; rancid.
  "sappie or unsavourie flesh"