"full of sap," Late Old English sæpig, from sæp (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).
权威例句
1. Do not overfeed them, as this will encourage soft sappy growth.