1. To check; keep in check (a fire).
2. To lessen in force or effect; SYN. damp, soften, weaken, break.
3. To quieten or silence (a sound) or make (an image) less visible; SYN. muffle, mute, deaden, damp, tone down.
4. To reduce the amplitude (of oscillations or waves).
(Alternate spelling: demoralise).
To corrupt or undermine in morals; to destroy or lessen the effect of moral principles on; to render corrupt or untrustworthy in morals, in discipline, in courage, spirit, etc.; to weaken in spirit or efficiency.