English to English
1. being effective without wasting time or effort or expense
an efficient production manager|efficient engines save gas
2. Causing effects; producing results; that makes the effect to be what it is; actively operative; not inactive, slack, or incapable; characterized by energetic and useful activity; as, an efficient officer, power.
3. able to accomplish a purpose; functioning effectively
people who will do nothing unless they get something out of it for themselves are often highly effective persons...|effective personnel|an efficient secretary|the efficient cause of the revolution
4. An efficient cause; a prime mover.