Validity (noun)
The state of being valid, authentic or genuine.
Validity (noun)
Having legal force.
Validity (noun)
A quality of a measurement indicating the degree to which the measure reflects the underlying construct, that is, whether it measures what it purports to measure (see reliability).
Reliability (noun)
The quality of being reliable, dependable{{,}} or trustworthy.
“dependable”
“unreliable”
Reliability (noun)
the ability to measure the same thing consistently (of a measurement indicating the degree to which the measure is consistent); that is, repeated measurements would give the same result (See also validity).
Reliability (noun)
– measurable time of work before failure
Wiktionary