(rare, nonstandard) Efficacious.

making good, thorough, or careful use of resources; not consuming extra. Especially, making good use of time or energy

(obsolete) a cause; something that causes an effect

The extent to which time is well used for the intended task. / (dated) The quality of producing an effect or effects.

plural of efficiency

In an efficient manner.

The quality of being efficient; efficiency.

Archaic form of efficiency.

plural of efficience

plural of efficient