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.