1.
[שָׁוְא] (shav)
...denotes that which is vain and transitory as regards both value and permanence.
[מַת] (math) ...are people who have no worth at all for the present and are of value only insofar as they serve as a transition to coming generations that may be superior to them.
methei-shove - are those who have no conception of the deeper meaning of life and have room in their minds only for vain and transitory things. It is impossible to avoid contact with such people but “I have never sat down with them, I have not ever intentionally dwelt in their company. I have always avoided the company of men who do not fear God, but who do dread men and therefore find it necessary to dissemble their true nature and character from the eyes of other persons."