"full of sap," Late Old English s?pig, from s?p (see sap (n.1)). Figurative sense of "foolishly sentimental" (1660s) may have developed from an intermediate sense of "wet, sodden" (late 15c.). Earlier, now obsolete, figurative senses were "full of vitality" (1550s) and "immature" (1620s).
雙語例句
1. Do not overfeed them, as this will encourage soft sappy growth.