ef·fec·tive adj1: producing a desired effectan effective revocation of the contract2: capable of bringing about an effect3: being in effect4 of a rate of interest: equal to the rate of simple interest that yields the same amount when the rate is paid once at the end of the interest period as a quoted rate of interest does when calculated at compound interest over the same period compare nominalef·fec·tive·ness n
Merriam-Webster’s Dictionary of Law. Merriam-Webster. 1996.
able, adapted, adequate, advantageous, capable, competent, convenient effectual, efficacious, efficax, equal to, expedient, fit, functional, handy, helpful, implemental, instrumental, of service, of use, practicable, practical, pragmatic, productive, proficient, profitable, serviceable, skillful, successful, to the purpose, unerring, up to, useful, utilitarian, valid
active, at work, effectual, fit for use, having legal force, in action, in effect, in force, in operation, operational, ready for use, usable, valid, working
associated concepts: effective assignment, effective at death, effective date, effective dissolution
active, capable, causal, cogent, competent, constructive (creative), efficient, eloquent, expert, felicitous, functional, incisive, influential, material (important), omnipotent, operative, persuasive, politic, potent, powerful, practical, predominant, prevailing (having superior force), proficient, sound, strong, successful, valid, valuable, viable
Burton's Legal Thesaurus. William C. Burton. 2006