effectual (adj.)

"producing an effect; having power to produce an effect," late 14c., Old French effectuel, from Late Latin effectualis, from Latin effectus "accomplishment, performance" (see effect (n.)). Used properly of actions (not agents) and with a sense "having the effect aimed at" (effective, by contrast, is used of the agent or the thing done and with a sense "having great effect"). Related: Effectually; effectualness.