effectual

 
Pronunciation: /ɪˈfɛktʃʊəl, -tjʊəl/

adjective

  • (of something inanimate or abstract) successful in producing a desired or intended result; effective: tobacco smoke is the most effectual protection against the midge
  • Law (of a legal document) valid or binding.

Derivatives

effectuality

Pronunciation: /-ˈalɪti/
noun

effectually

adverb

effectualness

noun

Origin:

late Middle English: from medieval Latin effectualis, from Latin effectus (see effect)