SAP

Definitions

1. 1. To subvert by digging or wearing away; to mine; to undermine; to destroy the foundation of. Nor safe their dwellings were, for sapped by floods, Their houses fell upon their household gods. Dryden.
2. 2. To pierce with saps.
3. 3. To make unstable or infirm; to unsettle; to weaken. Ring out the grief that saps the mind. Tennyson.