" efficacy "

 [ "efficacy" ]

1:  The division of the product of a unit's hit points and damage by its attack period

  * e.g.,  ... A rifleman's efficacy turns out to be 7070. 

 [ "efficacy" ]

2:  The derivative of impact

 [ "efficacious" ]

1: A douchey way of saying effective.

  * e.g.,  ... When trying to impress with his vocabulary by using the word 'efficacious' rather than 'effective', the man was actually more efficacious at sounding like an ass. 

 [ "efficacious" ]

1: An adjective (descriptive word): Describing thing, or person, producing, or sure to produce, desired effect. "Efficaciously" (adverb) describing the behaviour of act in such a manner as to effect the desired effect.

  * e.g.,  ... Asprin is truly "efficacious" for the treatment of headaches. I've never known a teacher to be so consistent in dealing so "efficaciously" with problem students, as he does. 

 [ "efficacious" ]

2: I may help to understand that the Latin root for these words is the same as that for "Efficient".

 [ "self-efficacy" ]

1:  when a person believes in their own ability to complete a task. when someone poops themself.

  * e.g.,  ...  Self-efficacy led Stephanie to believe she could make good marks on the exam. Stephanie was unable to finish the exam due to self-efficacy.