“effective” in Latin

efficax (general term caelius, ap. Cic.; Liv.; not Cic., or Caes.): valens (strong, powerful, etc., both of things, as medicines, proofs, etc., and of persons; e.g., a logician, dialecticus): fortis (strong, of medicines, etc): praesens (exercising immediate influence; e.g., medicines: praesentaneus post-classical): potens (powerful; of medicines, arguments, etc., mostly poetical, and in post-Augustan, prose).”Effective of anything” (Bacon, Taylor, etc.), efficiens alicujus rei (Cic.), also effector or effectrix alicujus rei. ☞ Effectivus occurs in effectiva ars (Quint., 2, 18, 5), ποιητική; that is, neither merely contemplative nor terminating in the act (like dancing), but leaving some effect or product behind it. Effective against anything, *valens adversus aliquid: to be effective, vim habere (☞ not vim exserere); efficacem esse: to be very effective, magnam vim habere: we must take more effective measures, fortioribus remediis utendum est (Liv.): the engines now began to prove effective, opera jam erant in effectu. An effective cause, causa efficiens (Cic.): quod alicui rei efficienter antecedit. To be effective of anything, efficientem esse alicujus rei (e.g., virtus efficiens est voluptatis).

As a military term, qui arma ferre or munus militiae sustinere potest (from health, strength, etc.; ☞ Caes., B.G., 6, 18; Liv., 22, 11): the army consists of ten thousand effective men, decern millia in armis sunt.