
1) Latin boy name
Found on
https://www.crosswordclues.com/clue/placidus

Latin, meaning: quiet, still, gentle.
Found on
http://archives.nd.edu/ppp.htm

Placidus is Latin for `placid, gentle, quiet, still, calm, mild, peaceful` and can refer to: ...
Found on
http://en.wikipedia.org/wiki/Placidus
[martyr] Saint Placidus (Placitus), along with Saints Eutychius (Euticius), Victorinus and their sister Flavia, Donatus, Firmatus the deacon, Faustus, and thirty others, have been venerated as Christian martyrs. They were said to be martyred either by pirates at Messina or under the Emperor Diocletian. In their `Acts,` this Placidus was con...
Found on
http://en.wikipedia.org/wiki/Placidus_(martyr)

quiet, still, gentle.
Found on
https://www.math.ubc.ca/~cass/frivs/latin/latin-dict-full.html
No exact match found.