Phintys (Φιντύς, 4th c. BCE) was the Pythagorean philosopher, daughter of Callicrates, author of a treatise On the Temperance of Women — one of the few surviving philosophical works attributed to a woman from antiquity.
Fragments preserved in Stobaeus.
Phintys does not currently appear in the US Social Security Administration's top 1,000 girls' names, so we don't publish a US rank or birth count for it. That says nothing about the name's standing elsewhere in the world — only that it sits outside the ranked US data we rely on.
In Pythagorean numerology the letters of Phintys reduce to 3, The Communicator. This is a traditional interpretive system, not a factual claim about the name.