Faith and lake
A modern American compound name combining the virtue name Faith with the popular suffix -lyn. Faith is derived from the Latin 'fides', while -lyn is often associated with the Welsh word for lake.
Less common today
Faithlyn isn't in the latest US Top 1000. It last peaked at #4,217 in 2013.
US births per 5-year period, 1990βpresent (SSA data).