efficacious
adjective
1. marked by qualities giving the power to produce an intended effect
- written propaganda is less efficacious than the habits and prejudices...of the readers
- the medicine is efficacious in stopping a cough
Similar word(s): effective, effectual, efficacious, effective
2. producing or capable of producing an intended result or having a striking effect
- an efficacious law
Similar word(s): trenchant, impelling, impressive, telling, efficacious, efficient, potent, stiff, strong, powerful, useful, utile, effective, effectual