ETYM Latin effectivus: cf. French effectif.
1. Able to accomplish a purpose; functioning effectively; SYN. efficient.
2. Producing or capable of producing an intended result or having a striking effect; SYN. effectual, efficacious.
3. Working well as a means or remedy.
4. Existing in fact; not theoretical; real.
5. Exerting force or influence; SYN. good, in effect, in force.
6. (Military) Equipped and ready for service.