making good, thorough, or careful use of resources; not consuming extra. Especially, making good use of time or energy
expressing the proportion of consumed energy that was successfully used in a process; the ratio of useful output to total input
causing effects, producing results; bringing into being; initiating change (rare except in philosophical and legal expression efficient cause = causative factor or agent)
effective, efficacious
Able to provide for one's own needs without help from others; self-sufficient.
Able to sustain itself without the need for additional fuel.
Opposing or rejecting exterior influence; independent.