valid-, val-, vale-, -vail, -valent, -valence

(Latin: valere, to be strong, to be well, to be worth; strong; power, strength; and "fare well" [go with strength])

Non est vivere sed valere vita est.
Life is not being alive but being well.

Also translated as, "Life is more than just being alive."

Potent sexually only in unusual circumstances.
prevail (verb), prevails; prevailed; prevailing
1. To be greater in influence or strength; to triumph: Virginia hopes that someday peace will prevail on earth and wars will be something of the past.
2. To be or become effecive; to win out: In making decisions in town, Jack thought that common sense and fairness would prevail.
3. To be in current usage; to persist: Some traditions and customs do prevail in many western countries, like Easter, Thanksgiving, and Christmas.
4. To persuade effectively and favorably: Nigel prevailed on his mother to let him go to the movies with his friends.
prevalence (s) (noun), prevalences (pl)
1. A huge amount or exceeding in numbers: Mr. Smart told his students that there was a prevalence of spelling mistakes in their tests which meant that they would have to spend much more time practising spelling!
2. The quality of predominance; widespread: There was a prevalence of buoyancy and hope among the students in the classroom when they heard that their last exam turned out to be very good!
3. The ratio of the number of incidents of an illness in a certain time period to a specific number of people in the population: The prevalence of the virus was greater in the southern countries than in the northern ones within Europe.
prevalent (adjective); more prevalent, most prevalent
Referring to something which is common or most frequent: One type of criminal offence seemed to be quite prevalent at night in the town when the criminals stole expensive items from some cars parked in the side streets.
Sexually potent only in the prone position.
Quomodo vales?
How are you?

Another Roman greeting just as it is another English greeting.