Russian-English translations for де́йственный

• effective
  The pill is an effective method of birth control
  The president delivered an effective speech!
  How long does it take to make a bunch of civilians an effective military force?
• efficacious
  This medicine is efficacious
• operative
  Hes usually in a good mood — the operative word there being "usually". Today was a disaster.
  an operative motive
  an operative dose, rule, or penalty