- effervescent salt,
- efficiency apartment
Origin of efficacious
Examples from the Web for efficacious
I asked him if he thought cattle cars would be an efficacious means of transporting the Palestinians to their new homes.
Sticky, but efficacious, and sucked a chocolate all the time, to make my voice thick.A Houseful of Girls|Mrs. George de Horne Vaizey
The application of either extreme heat or cold to the joint is agreeable and efficacious.Surgery, with Special Reference to Podiatry|Maximilian Stern
I beg also that you will not forget how efficacious is flannel when worn next to the skin.