1. Strong; powerful; efficient. [Obs.] "Perhaps more valid arms . . . may serve to better us." Milton.
2. Having sufficient strength or force; founded in truth; capable of being justified, defended, or supported; not weak or defective; sound; good; efficacious; as, a valid argument; a valid objection.
"An answer that is open to no valid exception." -- I. Taylor.
3. (Law) Having legal strength or force; executed with the proper formalities; incapable of being rightfully overthrown or set aside; as, a valid deed; a valid covenant; a valid instrument of any kind; a valid claim or title; a valid marriage.
Syn. -- Prevalent; available; efficacious; just; good; weighty; sufficient; sound; well-grounded.